Pick imitation nursing attire, 50% off (7)
I believe the answer is:
mattock
'pick' is the definition.
(tool similar to a pickaxe)
'imitation nursing attire 50 off' is the wordplay.
'imitation' becomes 'mock'.
'nursing' is an insertion indicator.
'50 off' means to take half the letters (50 per cent of the letters taken off).
'attire' with half the letters taken is 'att'.
'mock' placed around 'att' is 'MATTOCK'.
(Other definitions for mattock that I've seen before include "Pickaxe with one flattened end" , "Pickaxe-like tool" , "Pick" , "it may be groundbreaking" .)