Clothes appear dishevelled on student (7)
I believe the answer is:
apparel
'clothes' is the definition.
(synonyms)
'appear dishevelled on student' is the wordplay.
'dishevelled' indicates an anagram.
'on' means one lot of letters go next to another.
'student' becomes 'L' (as in L-plates for learner drivers).
'appear' anagrammed gives 'appare'.
'appare'+'l'='APPAREL'
(Other definitions for apparel that I've seen before include "Formal word for clothing" , "formal dress?" , "Attire" , "what's in the press?" , "Raiment" .)