Party wrong to turn on a pretty boy (6)
I believe the answer is:
adonis
'pretty boy' is the definition.
(I've seen this in another clue)
'party wrong to turn on a' is the wordplay.
'party' becomes 'do' (do is a kind of party).
'wrong' becomes 'sin' (wrong can mean a sin or crime).
'to turn' says the letters should be written in reverse.
'on' means one lot of letters go next to another.
'sin' reversed gives 'nis'.
'do'+'nis'='donis'
'donis' put after 'a' is 'ADONIS'.
(Other definitions for adonis that I've seen before include "Greek idol" , "Handsome Gk. youth" , "striking youth" , "A very handsome legendary Greek" , "Fit bloke" .)