Inconsistent comedian at last packing questionable venue (6)
I believe the answer is:
uneven
'inconsistent' is the definition.
(I've seen this before)
'comedian at last packing questionable venue' is the wordplay.
'at last' suggests the final letters.
'packing' is an insertion indicator.
'questionable' indicates anagramming the letters.
The final letter of 'comedian' is 'n'.
'venue' anagrammed gives 'ueven'.
'n' placed inside 'ueven' is 'UNEVEN'.
(Other definitions for uneven that I've seen before include "Rough on the surface" , "Rough, jagged" , "That's odd" , "Ill-matched - irregular" , "Odd - rough" .)