Disgraceful chap swallowing drug (4)
I believe the answer is:
mean
'disgraceful' is the definition.
(thesaurus)
'chap swallowing drug' is the wordplay.
'chap' becomes 'man' (I've seen this before**).
'swallowing' indicates putting letters inside.
'drug' becomes 'e' (e is another name for ecstasy).
'man' placed around 'e' is 'MEAN'.
(Other definitions for mean that I've seen before include "Stingy; Scrooge-like" , "Intend, plan" , "Spiteful -- excellent (slang)" , "Signify; miserly" , "Bad-tempered" .)