What it means
To keep mum means to stay quiet and not spill the beans, especially when you’ve been trusted with gossip or a secret. It can sound a bit old-school, like something your nan would say, but it still pops up at work and in family drama. Basically, zip it and don’t be that person.
Usage examples
"Boss said keep mum about the redundancy list, but Dave had already texted the whole team before the kettle even boiled."
"My nan said to keep mum about the surprise birthday for grandad, then promptly told the butcher, the postwoman and three random strangers at the bus stop on the way to Tesco."
"Keep mum about the new manager being the boss daughter, the rumour mill will spin on its own, we do not need to add fuel to the conversation by the kettle on Monday morning."
Where it comes from
Mum here is the Middle English mum, the unintelligible mumble of closed lips, the sound of someone choosing silence. Keep mum kept its old shape through Shakespeare and the British wars when not spilling the beans could save a life. Today it lives mostly in offices, family kitchens and the polite corner of British workplace gossip.
Other ways to say it
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