Loose woman in the family taking top off (5)
I believe the answer is:
untie
'loose' is the definition.
(loose can mean to untie or unleash)
'woman in the family taking top off' is the wordplay.
'woman in the family' becomes 'auntie' (I've seen this before).
'taking top off' means to remove the first letter.
'auntie' with its initial letter taken off is 'UNTIE'.
(Other definitions for untie that I've seen before include "Undo, unlace" , "Detach" , "Remove fastenings from" , "Free from binds" , "Remove ropes, unfasten" .)