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Indubitably — Meaning, Usage, Synonyms & Antonyms

Indubitably — Meaning, Usage, Synonyms & Antonyms

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Curious about how native speakers increase the strength of their ideas and arguments in speech or writing?

Apart from using advanced, uncommon, and idiomatic expressions, native English speakers also drive persuasion by using intensifying adverbs.

Lo and behold! Let this post tickle your brains for a few minutes, wherein you’ll discover the nuances behind the word “indubitably.”


What does “indubitably” mean?

“Indubitably” is an adverbial intensifier that means leaving no room for any doubt or uncertainty. We can modify verbs, adjectives, and adverbs with “indubitably.” Also, we can use it as a more powerful alternative response to “absolutely,” “for sure,” or “certainly” when agreeing to an idea.


Understanding “indubitably” in detail

“Indubitably” comes from the root word “doubt” which means “uncertainty” as a noun and “to feel uncertain” or “to have second thoughts” as a verb.

It is an adverb that intensifies or increases the strength of another expression or idea embedded somewhere else in the sentence.

New York is indubitably the most expensive city to live in the USA.

It can also be used as a single-word affirmative response after a statement or question when and if one thinks that the preceding utterance is precisely true.

A: Financially speaking, do you think it’s hard to live in New York City?

B: Indubitably. That’s why I finally decided to return home.

We can say that “indubitably” works pretty much like “absolutely” or “exactly” when used in agreeing with an idea, but it contains more force or power.

Therefore, a person using “indubitably” in a sentence aims to imply that the idea he or she is admitting or pertaining to is irrefutable, irreversible, and indisputable.

In a nutshell, the use of intensifiers like “indubitably” aims to influence the perception of the listener or reader in favor of the writer or speaker’s intention to persuade through language use.


Forming the word “indubitably”

To understand the word-formation process in “indubitably,” we can dissect it into four major parts.

We will look into its root word, prefix, and suffixes in the following subsections.


The root word “doubt”

“Doubt” can be used in two different senses, namely, as a noun and as a verb, in which the underlying meaning boils down to the state or feeling of uncertainty or hesitation.

The noun sense of “doubt” can be countable or uncountable depending on the context where it is used.

Countable: His congruous words and actions chased away all of her doubts.

Uncountable: Doubt can only be removed through action.

Whereas, the verb sense of “doubt” (to doubt) refers to the state of being uncertain, which is related to thoughts and opinions.

Stative verbs are generally not expressed nor accepted in the progressive or continuous tense as opposed to action verbs because they are not physically observable.

Here’s an example of using “doubt” as a verb.

They still doubt your skill at this point.


The prefix “in-”

A prefix is a letter or set of letters added at the beginning of a word to alter its meaning or usage.

“Indubitably” is headed by the prefix “in-” which means “not,” thereby reversing the negative connotation of the root word “doubt” in the process.

This prefix is also used in the same “not” sense in the following words: incongruously, indiscreetly, insanely, and inconspicuously.

However, “in-” may also be used to mean “against” as in “indemnify,” “inhibit,” and “indict.”

Its other sense, which means “in, on, upon, or into,” can be observed in words like “inscribe,” “ingratiate,” “induce,” and “insinuate.”


The adjectival suffix “-able”

The adverb “indubitably” is also formed from the adjective “indubitable” which contains the suffix “-able.”

This suffix, which is also separately categorized as an adjective, means “having the capacity, power, way, or skill” of doing something or “handy.”

We can add suffixes to words that are either a noun or a verb such as “drink,” “debate,” “work,” and “break” with “-able” to form them into adjectives.

Verbs such as “avoid, “adapt,” “apply” may also be turned into “avoidable,” “adaptable,” and “applicable.”


The adverbial suffix “-ly”

As experts put it, adverbs are like a rag-bag category in the language system because of how messy they are.

It is more difficult to teach the meaning and usage of adverbs to language learners compared to nouns, verbs, and adjectives.

Although this is the case, this challenge is at least compensated by how easily we can create adverbs from adjectives.

This can be achieved by adding the suffix “-ly” to the base adjective, such as in “slowly,” “massively,” “courteously,” and “guiltily.”

But, we have to bear in mind that not all words ending in “-ly” are adverbs, as some of them are plain adjectives, like “lovely,” “costly,” and “deadly.” 

Some words ending in “-ly” can also be used either as an adjective or an adverb depending on the sentence structure and context, such as “daily” and “lowly.”


Forming phrases and sentences with “indubitably”

Adverbs serve their purpose by highlighting or emphasizing the word or words they modify, which are mainly adjectives, verbs, or other adverbs.

Doing so, once again, improves the meaning of the statement by making it more intense, and hence, convincing to the reader or listener.

Here’s a sentence without an intensifier.

You are talented.

And, here’s another sentence containing one.

You are indubitably talented.

Imagine hearing the two examples as compliments given to you by two different people after your live performance as a one-man band in a small yet cozy café.

Indubitably enough, the remark with an intensifier should boost your self-confidence more than the other.

Now, let’s also look at the different ways to use “indubitably” in a sentence using easy-to-remember syntactical patterns.


Indubitably + adjective

 If you want to intensify your adjective with “indubitably,” you can simply add an adjective afterward.

Here’s a sentence with a positive connotation.

That is an indubitably brilliant idea!

And, here’s one which can be a double-edged sword, proving the essence of context and further information to be fully understood.

You are indubitably the most sensitive person I’ve ever known.


Indubitably + verb

We may also use “indubitably” with a verb to shift the focus to the action or state rather than the other parts of the sentence.

Let me show you a sentence bearing a positive implication.

Diane indubitably proved that she can succeed without her parents’ financial resources and connections.

And another one with a rather negative meaning.

Stacy indubitably believes all the lies that he says.


Indubitably + adverb

Adverbs may also be modified by other adverbs, which is a notable function of intensifiers.

Here’s a sentence using two intensifiers situated beside each other in the same sentence that draws even more emphasis to the idea being described.

She is indubitably too selfish to notice her people’s needs.

And here’s another way to modify another adverb.

Paula would indubitably never have to deal with him again.


Related words to “indubitably”

Now that we’ve covered how “indubitably” is formed, as well as how it works within a sentence, let’s also have a look at our intensifier’s siblings.

You will also learn how to use each of them in a sentence.



When you remove the prefix “in-,” what remains is the affirmative form of the adverbial intensifier in our discussion.

Since you’ve already understood that the prefix “in-” means “not,” then it should follow that the meaning of “dubitably” is can be equated to something that is “doubtful” or “uncertain.”

I’m not sure whether I could rely on your dubitably clear memory.

In the sentence above, the juxtaposition of “dubitably” and “clear” suggests a rather poetic language application.

This may occur when one intends to use language in a stylistic manner for the sake of rhetoric.



In case you don’t want to use the adverbial intensifier “indubitably,” you may conveniently adjust your sentence by using the adjective form instead.

The adjective form of “indubitably” is “indubitable,” which you can use as in the next example sentence.

All his arguments are indubitable.

An “indubitable argument” is something that leaves no room for doubt, protest, or object, or, in other words, solid and logical.



On the flip side, the adjective “dubitable” may be used to convey the meaning “doubtful,” “questionable,” “confusing,” or “debatable.”

Thus, anything that is “dubitable” is neither a solid nor strong idea at all, leaving lots of room for invalidation.

The disappearance of the Mayan civilization remains dubitable to date.

In the sentence above, “dubitable” serves as as subject complement, which means it provides a definition about the complete subject “the disappearance of the Mayan civilization.”



“Indubitability” is one of the two noun forms of the adverb “indubitably,” which can be used either as a subject or object in a sentence.

The noun form “indubitability” is the state or quality of being unquestionable or clearly true.

Knowing the noun form of “indubitably” allows us to calibrate and repurpose our sentences, either in spoken or written English.

Here’s how we can use it.

Richard Rorty says that indubitability is the mark of eternal truth.



The other noun form of “indubitably” is “indubitableness,” which still means “certain” or “absolutely true and valid.”

“Indubitability” refers to the quality of being unquestionable or certain, and “indubitableness” is the state or quality of being “indubitable.”

While “indubitability” either works as a countable or non-countable noun, “indubitableness” does not.

Here’s a sentence using this noun form.

The indubitableness of parental love makes unimaginable sacrifices possible.


Frequently Asked Questions on “indubitably”


What is a synonym for “indubitably”?

“Unquestionably,” “indisputably,” and “undoubtedly” are synonymous to “indubitably.” The idiomatic phrase “beyond any shadow of doubt” is also another way to express it.


What is an antonym for “indubitably”?

“Uncertainly,” “arguably,” and “disputably” are antonyms of “indubitably”, and the phrase “to be in two minds” is an idiomatic equivalent.


How can we use “indubitably” in a sentence?

“Indubitably” is used as an adverbial intensifier which could modify verbs, adjectives, or other adverbs as in: “indubitably generate promising results,” “an indubitably obsolete word,” and “indubitably too young to start a family.


If you have reached this part of the post, then you are indubitably a Linguaholic! 

A huge thank you for sticking around, and see you in our next article!