When you hear the phrase “mum’s the word,” you might assume a British person is talking about their dear old mother. But the expression has nothing to do with anyone’s parents. Instead, it means to stay silent, and it’s usually used in reference to keeping a secret.
The word “mum” comes from the Middle English “mommen” — a verb meaning “to speak softly or remain silent” — which was coined circa 1400. By the late 15th century, the word “mom” (sometimes spelled “mum”) came to mean “an inarticulate closed-mouth sound,” according to the Online Etymology Dictionary. This sound showcased an inability or unwillingness to speak openly and freely.
During the 16th century, people began to say “mum is counsel,” with “counsel” meaning “advice.” This phrase meant it was in someone’s best interest to keep their mouth shut. The Oxford English Dictionary cites several examples of this phrase throughout the 16th century. In the late 17th century, the words “is counsel” were swapped out for “the word,” and so “mum’s the word” became the most common wording thereafter.
The word “mum” by itself became particularly popular thanks to William Shakespeare’s 1591 play Henry VI, Part 2. During an Act 1 monologue, the character Sir John Hume says, “Seal your lips, and give no words but ‘mum’” — essentially duplicating the meaning of “mum’s the word.” Given Shakespeare’s popularity, it’s fair to say that his use of the term helped make it, and the relation to silence, more common in society’s collective vernacular.
More from our network
Word Smarts is part of Optimism, which publishes content that uplifts, informs, and inspires.
