noun

• (Commonwealth, Ireland, informal) Mother.
  "From the Marvel Mixmaster to the Miracle Microwave, every time a new-fangled gadget has lobbed into the Aussie kitchen, Aussie mums have changed their cooking styles accordingly."

noun

• (chiefly US) A chrysanthemum.
  "I don't know whether that's true or whether New Yorkers are being enjoined from watering the mums in their window boxes or whatever, but I do know that there hasn't been one rain-delay in the whole tournament so far […]."
• (US, originally Texas) A decoration made originally of a real chrysanthemum but now usually an artificial (silk) flower combined with ribbons and marked with such indicators as the wearer's name, school name, the year, and so on; traditionally worn by girls at high school homecoming celebrations.

adj

• (colloquial or archaic, of a person) Silent.
  "The citizens are mum, and speak not a word."
• (colloquial) Secret.
  "“Come here, friend,” sternly from the doctor. “Now I give you the way inside if you’ll promise to keep it mum.”"

verb

• (UK, slang, obsolete, transitive) To silence.
  ""Well, Sal, you mum your dubber pretty generally, but when you do slacken your glib you may as well do it civilly.""