Wearing coat he is perverted and immature (8)
I believe the answer is:
inchoate
'immature' is the definition.
(I've seen this before)
'wearing coat he is perverted' is the wordplay.
'wearing' becomes 'in' (wear in (and 'in' is fashionable)).
'is perverted' is an anagram indicator.
'coat'+'he'='coathe'
'coathe' with letters rearranged gives 'choate'.
'in'+'choate'='INCHOATE'
'and' is the link.
(Other definitions for inchoate that I've seen before include "Immature" , "Just begun, not yet fully developed" , "Not established" , "just beginning" , "Confused" .)