Wearing retro Levis or elegant clothes (7)
I believe the answer is:
erosive
'wearing' is the definition.
(I've seen this before)
'retro levis or elegant clothes' is the wordplay.
'retro' says the letters should be written backwards (retro is Latin for 'backwards').
'clothes' indicates the answer is hidden within the clue (the letters clothe the hidden word).
'evisore' is hidden within 'levis or elegant'.
'evisore' written backwards gives 'EROSIVE'.
(Other definitions for erosive that I've seen before include "Tending to wear away" , "Wearing away" .)