Those hunting for Oscar nab Paul, seek Dicky (11)
I believe the answer is:
unspeakable
'those hunting for oscar' is the definition.
(Oscar Wilde called foxhunters unspeakable)
'nab paul seek dicky' is the wordplay.
'dicky' is an anagram indicator (dicky can mean ill or non-functioning).
'nab'+'paul'+'seek'='nabpaulseek'
'nabpaulseek' is an anagram of 'UNSPEAKABLE'.
(Other definitions for unspeakable that I've seen before include "The hardest tongue twisters are" , "Was Marcel Marceau's act so" , "Is impossible pronunciation so" , "dreadful" , "awful?" .)