This is the 184th most frequent Serbian word.
боље
"Better."
In this sentence, "боље" is an adverb describing how the action (in this case 'to perform') is being done, specifically indicating an improved quality or manner of the action.
Он ради боље у групи.
He performs better in a group.
Here, "боље" functions as a comparative adverb, suggesting a preferable choice or alternative to the subject's decision or perspective.
Боље је да идемо сада.
It's better that we go now.
In this usage, "боље" acts as a comparative adverb, comparing the state of feeling with a previous time, illustrating improvement in condition.