Rocky feints with right slug (7)
I believe the answer is:
snifter
'slug' is the definition.
(thesaurus)
'rocky feints with right' is the wordplay.
'rocky' indicates an anagram.
'with' means one lot of letters go next to another.
'right' becomes 'r' (common abbreviation).
'feints' anagrammed gives 'snifte'.
'snifte'+'r'='SNIFTER'
(Other definitions for snifter that I've seen before include "A wee dram" , "brandy glass" , "shot" , "14 [NIP]" , "Small alcoholic drink (colloq.)" .)