Coarse show embodying extremes of evil (10)
I believe the answer is:
indelicate
'coarse' is the definition.
(I've seen this before)
'show embodying extremes of evil' is the wordplay.
'show' becomes 'indicate' (synonyms).
'embodying' means one lot of letters goes inside another (to embody can mean to contain or include).
'extremes of' means to remove the middle letters.
'evil' with its centre taken out is 'el'.
'indicate' enclosing 'el' is 'INDELICATE'.
(Other definitions for indelicate that I've seen before include "lacking taste" , "Rather rude" , "Practised (a play)" , "Coarse" , "Rude - tasteless" .)