The phrase 'Mum’s The Word' is used when you mean to keep quiet or say nothing.
Example of Use: “Please don’t tell Mom what I’m getting her for her birthday.” Answer: “Mum’s the word!”
Interesting fact about Mum's the Word
The 'mum' in the expression 'mum’s the word' is derived from the humming sound a closed mouth makes, indicating an inability or unwillingness to speak. The word 'mum' was first used by William Langland in his 1376 work Piers Plowman, and the expression itself became popular in the 16th century. You’ll find it in Shakespeare’s Henry VI, Part 2: “Seal up your lips and give no words but mum.”
