Fed up with a lack of sense (4)
I believe the answer is:
deaf
'lack of sense' is the definition.
The answer and definition can be both to do with perception as well as being verbs in their base form.
Perhaps there's a link between them I don't understand?
'fed up with a' is the wordplay.
'up with' indicates anagramming the letters (letters get chucked up).
'fed' mixed up with 'a' can make 'DEAF'.
Can you help me to learn more?
(Other definitions for deaf that I've seen before include "With impaired hearing" , "Not prepared to listen" , "Deprived of the sense of hearing" , "Unable to hear" , "Rudely confident" .)