fair game

noun3

1. •
   A goal or an object that may legitimately be sought.

   • After the middle sister's call from a friend's house, her slice of cake was fair game.
2. •
   An acceptable subject or target for criticism, scrutiny, mockery, or attack.

   • Anyone running for office is fair game for criticism.
3. •
   Actions permissible by the rules.

   • Pretending to be slow is fair game. Pretending to be injured is not.
   • The referee ruled the unprecedented play fair game.