Joke ultimately unsavoury and feeble (4)
I believe the answer is:
puny
'feeble' is the definition.
(I've seen this before)
'joke ultimately unsavoury' is the wordplay.
'joke' becomes 'pun' (punning is a kind of joking).
'ultimately' indicates one should take the final letters.
The last letter of 'unsavoury' is 'y'.
'pun'+'y'='PUNY'
'and' is the link.
(Other definitions for puny that I've seen before include "Insignificant" , "Feeble, under-sized" , "Slight" , "Small and feeble" , "Frail and weedy" .)