Wear sound clothing or rejects? (7)
I believe the answer is:
erosion
'wear' is the definition.
(I've seen this before)
'sound clothing or rejects?' is the wordplay.
'sound' becomes 'noise' (noising is a kind of sounding).
'clothing' indicates putting letters inside (some letters cover up or clothe others).
'rejects?' says the letters should be written in reverse (I've seen 'reject' mean this).
'noise' enclosing 'or' is 'noisore'.
'noisore' reversed gives 'EROSION'.
(Other definitions for erosion that I've seen before include "Disintegration" , "Deterioration of soil etc" , "The wearing away as by wind or water" , "Mechanical process of wearing something down" , "A wearing away as of rock by water" .)