Look, talent and ability ultimately deficient (6)
I believe the answer is:
scanty
'deficient' is the definition.
(thesaurus)
'look talent' is the wordplay.
'look' becomes 'scan' (I've seen this before).
'talent' becomes 'ty' (I am not sure about this - if you are sure you should believe this answer much more).
'scan'+'ty'='SCANTY'
'and ability ultimately' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for scanty that I've seen before include "Sparse, meagre" , "Insufficient in amount" , "Modest" , "brief" , "Insufficient in quantity" .)