Partly discover allusion to this garment (7)
I believe the answer is:
overall
'this garment' is the definition.
(I've seen this before)
'partly discover allusion to' is the wordplay.
'partly' says the answer is hidden in the clue (part of the clue is used).
'OVERALL' is hidden in the letters of 'discover allusion to'.
(Other definitions for overall that I've seen before include "In total" , "Comprehensive - protective garment" , "Dress for dirty work" , "All round" , "Protective clothing" .)