mum's the word
The phrase "mum's the word" is an idiom that means to keep silent or to not disclose or reveal a secret or information. It is often used as an instruction to someone to remain quiet about a certain topic or situation. The word "mum" in this phrase refers to being quiet or silent.
English is confusing! Why do people say "Pardon my French" when they are speaking English? Because of idioms!
An idiom is a phrase or expression that usually presents a figurative, non-literal meaning attached to the phrase. Does that sound fun? It can be!
Play Just Saying - the word game that makes learning idioms a good time on your mobile phone or tablet.