Blockhead has quarrel at top of hill (4)
I believe the answer is:
brow
'top of hill' is the definition.
'brow' can be an answer for 'top' (brow can mean a summit or peak). I'm not certain of the 'of hill' bit.
'blockhead has quarrel' is the wordplay.
'blockhead' becomes 'b' (head letter of 'block').
'has' says to put letters next to each other.
'quarrel' becomes 'row' (synonyms).
'b'+'row'='BROW'
'at' acts as a link.
Can you help me to learn more?
(Other definitions for brow that I've seen before include "Summit of a hill/pass" , "Surprised one can raise this" , "Peak of a hill" , "Forehead, sometimes knitted" , "Crest" .)