Cat's pa (3)
I believe the answer is:
tom
'cat's pa' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tom that I've seen before include "- Lehrer, US humorist" , "Man's name; male cat" , "Queen's mate" , "Pig-stealing piper's son" , "Boy running off with pig" .)