keep a lid on

verb

verb

Idiomatic, Imperative To keep something secret.

It's supposed to be a surprise, so try to keep a lid on it, will you?
If he was listening to the England fans who gathered and sang non-stop late into the Moscow night behind the goal in the Spartak Stadium, it may have dawned on him that keeping a lid on expectations is likely to be a losing battle.2018 July 3, Phil McNulty, “Colombia 1 - 1 England”, in BBC Sport:

Entry derived from the Wiktionary, under licence CC BY-SA 4.0 — list of authors.