This is the 656th most frequent Chinese word.
肯定
"肯定" means "affirmation" or "definitely/affirmatively."
Here, '肯定' serves as an adverb to express confidence or definite possibility.
这次的比赛我们肯定能够赢。
We will definitely win this competition.
In this sentence, '肯定' is used as a verb meaning 'to be certain' or 'to affirm'.
我肯定他今天不会迟到。
I am certain he will not be late today.
In this case, '肯定' is a noun referring to 'approval' or 'acknowledgment'.