mum's the word

Idioms  

1. Say nothing about this, it's a secret, as in Mum's the word on tonight's surprise party. This expression dates from about 1700, but mum, meaning “silence,” is much older. In 2 Henry VI (1:2) Shakespeare wrote, “Seal up your lips, and give no words but mum.”

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Example Sentences

“You’re not wrong about any of it, but mum’s the word. The good Madame is in disguise. Here in the bakehouse we can speak freely. There’s no one near and the walls are solid stone. But outside this room, she’s Flora the Bread Lady. Understood?”

From Literature

Parker co-hosts the Mum's The Word podcast, and runs a performing arts school in Kent, wellbeing retreats, and a family travel company.

From BBC

While mum’s the word for now, Mosher hopes to soon announce good news on the horizon for fans of the restaurant.

From Seattle Times

Mum’s the word on which one will be pictured, but Schultz promised that “you’ll know who it is.”

From Seattle Times

Thinking back about those heady days at Crystal Sound, Mesaros points out that the surviving Smithereens are "jazzed about this project because, for the first time, we are producing ourselves, and mum's the word to the outside world. Somehow, it evokes the early days when we were our own best kept secret and a fan club of four."

From Salon