Drunken son in mum's hosiery? (6)
I believe the answer is:
tights
'mum's hosiery?' is the definition.
(a mother might wear tights)
'drunken son' is the wordplay.
'drunken' becomes 'tight' (I've seen this in other clues).
'son' becomes 's' (genealogical abbreviation for son).
'tight'+'s'='TIGHTS'
'in' acts as a link.
(Other definitions for tights that I've seen before include "Leg-wear for women" , "Pantihose" , "Women's garment worn in place of stockings" , "Types of stockings" , "elasticated clothing" .)