Endures, though finishing at one's wits' end (5)
I believe the answer is:
lasts
'endures' is the definition.
('last' can be a synonym of 'endure')
'at one's wits' end' is the wordplay.
'at one's' becomes 'las' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'wits'' becomes 'takeoffs' (takeoff is a kind of wit).
'end' says to hollow out the word (remove centre letters) (I've seen 'ends' mean this).
'takeoffs' with its centre taken out is 'ts'.
'las'+'ts'='LASTS'
'though finishing' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for lasts that I've seen before include "Keeps on" , "Endures" , "Goes on" , "Holds out" , "carries on" .)