Mother’s ruin? It’s a trap (3)
I believe the answer is:
gin
This clue is a double definition.
'mother's ruin?' is the first definition.
(I've seen this in other clues)
'a trap' is the second definition.
(gin is a kind of trap)
'it's' is the link.
(Other definitions for gin that I've seen before include "Spirit; trap" , "game of cards" , "It could be used for drinking" , "Trap for snaring small mammals" , "Trap; mother's ruin" .)