Top name - or should that be Smith? (5)
I believe the answer is:
brown
'top name or should that be smith?' is the definition.
The answer and definition can be both human attributes as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'top name' is the wordplay.
'top' becomes 'brow' (brow can mean a summit or peak).
'name' becomes 'n' (common abbreviation e.g. on forms).
'brow'+'n'='BROWN'
(Other definitions for brown that I've seen before include "Suntanned; sort of bear/study" , "Rugby hero" , "Dark - tanned - successor to Blair?" , "Colour - grill lightly" , "5,27 [PRIME MINISTER]" .)