‘Most Definitely’: Meaning, Proper Usage, and Alternative Phrases

By Carly Forsaith, updated on September 13, 2022

There is some debate around whether the expression ‘most definitely’ is correct because it doesn’t appear to follow the proper grammatical rules of the English language. However, it is often used. So is it correct to use it’? And if so, what is the right way to use it? 

Let us begin by confirming that 'most definitely' is absolutely a correct phrase and can be used in the English language without any qualms. 

If you'd like to know more about the meaning of the expression, proper usage, and alternative phrases, read on. All will be revealed in this article.

What Does “Most Definitely” Mean?

First, a definition of the phrase is in order, followed by a little grammar. Read on.


The expression ‘most definitely’ is used to express certainty around a subject. For instance, if someone asks you a question, you might answer with ‘most definitely’ to show your confidence around the fact that it is correct. For example:

Q: Do you believe aliens are real?

A: Most definitely.

But let’s break it down further.

A little grammar

‘Most’ is a superlative that stems from the word ‘many’. Superlatives are words that derive from adjectives or adverbs and are used to compare things. They show that something is of the highest or lowest quality. For example:

  • Sam is the best in his class. 
  • This cafe has the least options for vegans.
  • I'm the tallest of my friends. 

'Most' is the superlative for 'many', used in this case to show that the speaker has the most certainty about their opinion. 

‘Definitely’ is also used to express certainty. The word stems from the adjective 'definite', which means 'without uncertainty'. It shows that the speaker is 100% sure about something.

Therefore, using ‘most’ and ‘definitely’ together is a way of displaying absolute certainty about a topic. In other words, there’s no shadow of a doubt. 

Is “Most Definitely” Really Correct?

The reason for the debate around whether or not ‘most definitely’ is grammatically correct and can be used is because it’s a double affirmative, so the 'most' is often considered redundant. 

What makes it a double affirmative? The fact that the word 'most', which already conveys certainty, is combined with the word 'definitely', which also conveys certainty.

Double affirmatives 

Like double negatives, they tend to be disliked by some, as according to grammar rules they actually cancel each other out. Here are some examples of double negatives that are technically incorrect, but still used and understood by the listener: 

  • This won’t do you no good. 
  • You ain’t heard nothing yet.
  • There is no way you will not go.

Can you say it anyway?

There’s most definitely a lot of debate (see what we did there?) around whether or not it’s acceptable to use these double negatives and call it proper English. And the same goes for double positives like ‘most definitely'. 

But the truth is, the expression ‘most definitely’ is in fact correct and can be used in English. Some argue that you shouldn’t use it in formal contexts, however, many do exactly that and get away with it just fine. Trust us: nobody will call you up on this.

How Do You Use “Most Definitely” in a Sentence?

If you want to use the expression ‘most definitely’ in a sentence, how do you do that? And where would you place it?

Firstly, remembering the fact that to say ‘most definitely’ means you’re certain of something, then it makes sense that you would use it to express that certainty to another person. So a few scenarios where you might use it are when: you believe something; you agree with something; you’re sure of something; you intend on taking a specific action. Let’s see some examples of these scenarios below:

  • I most definitely believe that Toy Story 3 is the best of all the movies in the franchise.
  • Women are most definitely right when they say that sexism is still rife.
  • I will most definitely not be going to the party tomorrow.
  • I’ll most definitely be heading straight to the theatre as soon as the movie is released. 

You'll likely be able to see it from the examples above, but we'll explain further how to place 'most definitely' in a sentence.

First of all, let’s not forget that ‘most definitely’ can be used as a standalone sentence. So in answer to the question “Do you agree?”, for example, you can simply reply: “Most definitely”. You can also extend this sentence by adding a comma and then more words. So clearly, you can use 'most definitely' at the very beginning of a sentence.  

But as well as that, it can be used in a longer sentence. Here are a few ways you can set up your sentence:

  • subject + verb + 'most definitely' + action / object
    He is most definitely the man I want
  • Or even subject + 'most definitely' + verb + action / object
    I most definitely want to try that

Alternative Phrases

Which other phrases with the word 'definite' can you think of? And are there other ways to say 'most definitely'? That is what we are about to find out.

Do “Most Definite” and “Most Definitely” Mean the Same Thing?

No, these are not the same and they aren’t interchangeable. ‘Definitely’ is an adverb, whilst ‘definite’ can function as a noun or an adjective. So this is where things can get a little confusing. 

‘Definite’, when being used as a noun, means it’s a certainty, a guarantee, a given. Here’s an example of ‘definite’ being used as a noun:

That aliens exist is a definite. 

‘Definite’ when being used as an adjective acts to reinforce the noun it precedes. For instance, in the following example, the ‘definite’ just makes the ‘no’ stronger.

I told her we can’t go to the park. It’s a definite ‘no’. 

So when can you bring in the superlative ‘most’ and say ‘most definite’? When using ‘definite’ as an adjective, you can use ‘most definite’. In the example above, it would have been acceptable to say “It’s a most definite ‘no’”. Here are some other examples where it’s acceptable to say ‘most definite’:

  • Using antiseptic is the most definite way of getting that wound to heal.
  • The most definite pathway to getting into the club is to practice every day.

It’s worth noting that 'most definite' is best kept for more formal situations, or can be found in older conversations or texts. You'll seldom hear this being said in more casual conversations.

‘Most Definitely’ - Alternative Phrases

Okay, so let’s say you’re certain of something and you want to express this, but you’re not a fan of the phrase ‘most definitely’. Or maybe you just want to know a different way of saying it, so you’re not always using the same expression. 

We’ve got you! Below, we’ll list some alternative phrases you can use to show someone how certain you are.

  • Beyond a shadow of a doubt
  • With absolute certainty
  • No ifs, ands or buts about it
  • As sure as eggs is eggs
  • Sure as can be
  • One hundred percent
  • I'm positive
  • Most assuredly

What’s your favorite one? 

Let's Summarize

So to finish off, let's summarize. ‘Most definitely’ is correct and is commonly used in English. It comes in useful when you want to affirm to another person that you are 100%, beyond a shadow of a doubt, confident about the statement you are making, or an opinion you have. 

You can use it in a wide range of contexts and rest assured knowing that the listener/reader will understand your sentiment and that you won’t be judged for using incorrect grammar. 

You're most welcome!

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Written By:
Carly Forsaith
Carly Forsaith is one of the lead freelance writers for WritingTips.org. Carly is a copywriter who has been writing about the English language for over 3 years. Before that, she was a teacher in Thailand, helping people learn English as a second language. She is a total grammar nerd and spends her time spotting language errors on signs and on the internet.

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