Fed up with being drilled (5)
I believe the answer is:
bored
I believe this clue is a double definition.
'fed up' is the first definition.
(fed up can mean bored)
'being drilled' is the second definition.
(I've seen this in another clue)
'with' acts as a link.
(Other definitions for bored that I've seen before include "Brassed off" , "Fed up - tired of the world" , "Disaffected" , "Tired and uninterested" , "Extremely uninterested" .)