contest, game

試合(しあい)	A game: baseball, checkers, football, chess.

競争(きょうそう)	Unless a foot-race, not a game. competing within a framework. the best score on the test, the salesman who sold the most this month. business or academic.

競技(きょうぎ)	Games IN GENERAL. Like they don’t say ‘Olympic games’, they say ‘Olympic 競技’. Or ‘he really likes games’

争う(あらそう)	Competition. Unlike the synonym 競争（きょうそう）, 争う emphasizes a feeling of battle, a lack of rules, and only 争う can escalate to physical violence.

勝負(しょうぶ)	A win or lose situation. Fighting over a girl/boy. Not necessarily the final, decisive battle, the Superbowl. . The game/battle is won or lost on account of ..xxx. $$$

競う(きそう)	Get the best grade, most sales. competing within a system. 90% overlapping with 競争. Same usage. Fugeddaboutit.

闘う(たたかう)	A physical battle. but you can use it for a competition or sports, contest. not part of this set! life is a battle! not necc. with another person. battling with myself over an issue! man vs. nature fight for survival.