Neil upset band (4)
I believe the answer is:
line
'band' is the definition.
(band can mean a strip or line)
'neil upset' is the wordplay.
'upset' indicates anagramming the letters.
'neil' with letters rearranged gives 'LINE'.
(Other definitions for line that I've seen before include "Long mark; direction" , "Formation of one beside another" , "Row - occupation" , "column" , "Row; track" .)