Keep either end of flint? (4)
I believe the answer is:
fort
'keep' is the definition.
(I've seen this before)
'either end of flint?' is the wordplay.
'either' becomes 'for' (I can't explain this - if you can you should give a lot more credence to this answer).
'end of' suggests the final letters.
The last letter of 'flint' is 't'.
'for'+'t'='FORT'
Can you help me to learn more?
(Other definitions for fort that I've seen before include "Citadel" , "Keep" , "Military post in the old West" , "Defensive stronghold" , "US gold reserves are at - Knox" .)