Feline to get married (3)
I believe the answer is:
'feline' is the definition.
(tom is a kind of feline)
'to get married' is the wordplay.
'get' says to put letters next to each other.
'married' becomes 'm'.
(Other definitions for tom that I've seen before include "Thumb", "Repeated twice, this becomes an African drum", "queen's consort?", "Hoyden", "Pig-stealing piper's son".)