It covers the sharp end and everything else (4)
I believe the answer is:
pall
'it covers' is the definition.
The definition suggests a singular noun which matches the answer.
'sharp end and everything else' is the wordplay.
'end' suggests the final letters.
'and' means one lot of letters go next to another.
'everything else' becomes 'all' (I am not sure about this - if you are sure you should believe this answer much more).
The final letter of 'sharp' is 'p'.
'p'+'all'='PALL'
'the' is the link.
Can you help me to learn more?
(Other definitions for pall that I've seen before include "tedious here" , "Cloth over a coffin - become insipid" , "Become less appealing" , "Cloth covering a coffin" , "shadow" .)