AA, in a game Crossword Clue

 The answer to the crossword clue "AA, in a game" could be ACES.

In the card game of blackjack, the highest possible hand is a blackjack, which is an ace and a 10-value card.

In the card game of poker, aces are the highest-ranking card.

In the board game of Go, AA is a common abbreviation for "Atari", which is a situation where a player's stones are about to be captured.

In the video game of Tetris, AA is a common abbreviation for "Auto Arrange", which is a setting that automatically arranges the falling blocks.

Without more information about the specific game that the clue is referring to, it is impossible to say for sure which of these meanings is correct. However, aces is the most likely answer, as it is a common term in many different games.