definition of ''game''

Please check the following definitions of game from Merriam-Webster Dictionary. My questions will appear in red in superscript position.

¹game

1 a (1): activity engaged in for diversion or amusement : play (2): the equipment for a game b: often derisive or mocking jesting : fun, sport <make game of a nervous player>2 a: a procedure or strategy for gaining an end : tactic b: an illegal or shady scheme or maneuver : racket 3 a (1): a physical or mental competition conducted according to rules with the participants in direct opposition to each other (2): a division of a larger contest (3): the number of points necessary to win (4): points scored in certain card games (as in all fours^{What does all fours mean?}) by a player whose cards count up the highest (5): the manner of playing in a contest (6): the set of rules governing a game (7): a particular aspect or phase of play in a game or sport <a football team's kicking game> b plural : organized athletics c (1): a field of gainful activity : line <the newspaper game> (2): any activity undertaken or regarded as a contest involving rivalry, strategy, or struggle <the dating game^{What does dating game mean?}> <the game of politics>; also : the course or period of such an activity <got into aviation early in the game> (3): area of expertise : specialty 3 <comedy is not my game>4 a (1): animals under pursuit or taken in hunting; especially : wild animals hunted for sport or food (2): the flesh of game animals b archaic : pluck c: a target or object especially of ridicule or attack —often used in the phrase fair game<sup>What does fair game mean?

3</sup>game
1 a: having or showing a resolute unyielding spirit <game to the end^{What does game to the end mean?}> b: willing or ready to proceed <were game for anything>2: of or relating to game <game laws>