This is the 9469th most frequent Korean word.
경기다
"경기다" means to shudder or tremble with fear or disgust.
Here, '경기' is used to mean 'match' or 'game', with '-다' forming the predicate.
그 경기는 어제 끝났습니다.
The match ended yesterday.
'경기' here indicates a competitive event like a game or match, and '-를 위해' indicates 'for'.
오늘 경기를 위해 준비했습니다.
I prepared for the game today.
In this context, '경기' refers to the act or style within a game or match.