Smooth ale peculiarly obnoxious (9)
I believe the answer is:
loathsome
'obnoxious' is the definition.
(thesaurus)
'smooth ale peculiarly' is the wordplay.
'peculiarly' indicates anagramming the letters.
'smooth'+'ale'='smoothale'
'smoothale' is an anagram of 'LOATHSOME'.
(Other definitions for loathsome that I've seen before include "Repulsive" , "Disgusting, nauseating" , "Detestable" , "Horrid" , "15 [ABHORRENT]" .)