A hepcat? It is awful cool (9)
I believe the answer is:
apathetic
'cool' is the definition.
(thesaurus)
'a hepcat? it is awful' is the wordplay.
'is awful' indicates anagramming the letters.
'hepcat'+'it'='hepcatit'
'hepcatit' with letters rearranged gives 'pathetic'.
'a'+'pathetic'='APATHETIC'
(Other definitions for apathetic that I've seen before include "I hate pact, being disintersted" , "Unenthusiastic" , "Indifferent - without emotion" , "Impassive" , "disinclined to act" .)