If you have ever typed “definately” and hesitated before pressing send, you are definitely not the only one. This word is one of the most common spelling mistakes in English, showing up in messages, emails, essays, and even professional documents. The error usually comes from a small letter swap, but once you understand the rule, it becomes easy to avoid.
The correct spelling is also an important part of basic Grammar, especially for clear and professional writing.
Quick Answer
There is only one correct form:
✔ Definitely — correct
❌ Definately — incorrect
“Definately” is never correct in standard English.
Understanding this is a simple but important part of English Grammar.
Why People Misspell “Definitely”
Most mistakes happen because of pronunciation. When spoken quickly, the middle sound in “definitely” becomes unclear, so many people mistakenly replace the “i” with an “a.”
Another reason is the root word definite. If that word is spelled incorrectly, the mistake carries forward when “-ly” is added.
In English Grammar, this is a common issue: pronunciation does not always match spelling, and this word is a perfect example of that mismatch.
The Correct Spelling Explained
The word comes from definite, meaning certain or clearly decided. When you add “-ly,” you form an adverb:
definite + ly = definitely
Examples:

• I will definitely join the meeting.
• She is definitely the best choice for the role.
• That is definitely not what I said.

The correct spelling always preserves the “i” from “definite,” which is a key Grammar pattern to remember.
Why “Definately” Is Always Wrong
“Definately” is not a variation or alternative spelling. It is simply incorrect.
Unlike words such as:

• color / colour
• organize / organise

there is no accepted version of English where “definately” is correct.
All dictionaries and Grammar references agree that only “definitely” is valid.
Easy Way to Remember It
A simple memory trick is:
definite contains “finite,” and “finite” contains an “i”
So the chain is:
finite → definite → definitely
Another helpful breakdown is:
de-fin-ite-ly
Breaking the word into parts improves spelling accuracy and strengthens your understanding of Grammar patterns in English.
A simple reminder also helps:
No “a” in certainty — and no “a” in definitely.
Common Spelling Mistakes
People don’t only write “definately.” Other common errors include:

• definitley
• diffinitely
• definitly

All of these are incorrect spellings.
A useful Grammar rule to remember is that most English adverbs are formed simply by adding “-ly” to the adjective without changing its root spelling. That applies directly here.
Quick Comparison

Frequently Asked Questions
Is “definately” ever correct?
No. It is always incorrect in all forms of English writing.
Why do so many people misspell it?
Because pronunciation is unclear and the root word “definite” is often misspelled.
What type of word is “definitely”?
It is an adverb used to express certainty or strong emphasis.
How can I remember the correct spelling easily?
Focus on the root word “definite” and apply basic Grammar rules when adding “-ly.”
Final Thoughts
The confusion between “definitely” and “definately” is very common, but the solution is simple. Once you understand the root word and the correct spelling pattern, the mistake becomes easy to avoid.
Good Grammar is about recognizing patterns, and this is one of the simplest ones in English. By remembering “definite” and keeping the “i” in place, you will always choose the correct spelling.
With a little practice, your Grammar becomes stronger, your writing looks more professional, and you will never second-guess “definitely” again.