(idiomatic) To refrain from talking about something.

(American football) In the AFL, a warning given with one minute to go before the end of a half, after which special rules apply, eg, stoppage of the game clock after very first down.

(card games) In card playing, to accidentally reveal one's cards or hand. / (figuratively) To inadvertently reveal any secret, particularly a secret that puts one at an advantage or disadvantage.

(idiomatic) A recording artist known for only one hit song, especially after failing at subsequent attempts at success.

To behave in a manner appropriate to one's age. / (imperative, originally US) To behave in a mature manner; to avoid being childish.

(bingo) eight

(idiomatic) barely; closely; by a narrow margin; with nothing to spare.

(idiomatic) Located back at the start, as after a dead end or failure.

(idiomatic) Back to the start, as after a dead end or failure.

(idiomatic, often followed by on) To carry out a trick or deception; to behave contrary to expectations.