Meaning oftighten-upin English

Verb

1. to make something sufficiently tight
   You need to tighten-up the loose screws on the chair.
2. to become focused and serious; stop inconsistency
   The team will tighten-up their strategy to win the game.
3. to become tense and restrained (emotionally)
   After receiving the bad news, she began to tighten-up and didn't say a word.