https://www.vocabulary.com/articles/chooseyourwords/definitely-definitively/ Use definitely and definitively when there's no doubt, but save definitely for emphasis and definitively for the final say. If you definitely want to go to a party, but your mom definitively says no, then you aren't going. Quit asking. Definitely means something is definite — it's unmistakable and clearly defined. It's definitely getting warmer on this planet.