who's she—the cat's mother?

Who's she, the cat's mother?

A reprimand given to someone for using a pronoun ("she") instead of a proper name. A: "Oh, and she was there too." B: "Who's she, the cat's mother?"
Farlex Dictionary of Idioms.

Who's she, the cat's mother?

People say Who's she, the cat's mother? to show that they think it is rude when someone refers to a girl or woman as `she' instead of using their name. `Is she coming?' — `Who's she, the cat's mother?'
Collins COBUILD Idioms Dictionary, 3rd ed.

who's she—the cat's mother?

1 used as a mild reproof, especially to a child, for impolite use of the pronoun she when a person's name would have been more well mannered. 2 expressing the speaker's belief that a woman or girl has a high opinion of herself or is putting on airs. British informal
Farlex Partner Idioms Dictionary
See also:
  • appear under the name (of)
  • appear to
  • a change of heart
  • (one) can whistle for it
  • a mystery to (one)
  • a turn of phrase
  • able to do
  • able to do it
  • a shoulder to cry on
  • a piece/slice of the action