Boomer eats clothing, just (4)
I believe the answer is:
mere
'just' is the definition.
(I've seen this before)
'boomer eats clothing' is the wordplay.
'clothing' says the answer is hidden in the clue (the solution is covered or clothed by the clue).
'MERE' can be found hidden inside 'boomer eats'.
(Other definitions for mere that I've seen before include "Lake; Wiltshire town" , "Lake - French mother" , "Lake; simple" , "President Hollande's mother?" , "Lake in Cumbria" .)