A team apart (5)
I believe the answer is:
aside
'apart' is the definition.
(synonyms)
'a team' is the wordplay.
'team' becomes 'side' (both can mean a sports team).
'a'+'side'='ASIDE'
(Other definitions for aside that I've seen before include "Privately, apart" , "kept in reserve" , "Separately" , "In reserve; actor's remark to audience" , "Line spoken to theatre audience" .)