Upset, handle cross American feller (6)
I believe the answer is:
axeman
'feller' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'upset handle cross american' is the wordplay.
'upset' shows that the letters should be reversed in order.
'handle' becomes 'name' (handle can mean a name or nickname).
'cross' becomes 'x' (an X is a cross).
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'name'+'x'+'a'='namexa'
'namexa' backwards is 'AXEMAN'.
Can you help me to learn more?
(Other definitions for axeman that I've seen before include "Tree feller - executioner" , "who may give others the chop!" , "Guitarist (slang)" , "guitar player" , "Tree-cutter" .)