Servant returned don's crumpled suit (8)
I believe the answer is:
diamonds
'suit' is the definition.
(I've seen this before)
'servant returned don's crumpled' is the wordplay.
'servant' becomes 'maid' (maid is a kind of servant**).
'returned' is a reversal indicator.
'crumpled' indicates an anagram.
'maid' reversed gives 'diam'.
'dons' anagrammed gives 'onds'.
'diam'+'onds'='DIAMONDS'
(Other definitions for diamonds that I've seen before include "Precious stones from hard brilliant mineral" , "Precious gemstones" , "Pieces of the hardest known mineral" , "In song they're a girl's best friend" , "Precious stones found amid nods" .)