A team's pretentiousness? (4)
I believe the answer is:
side
I believe this is a double definition.
'a team's' is the first definition.
(both can mean a sports team)
'pretentiousness?' is the second definition.
(thesaurus)
(Other definitions for side that I've seen before include "Aspect, sports team" , "Dies (anag)" , "long forgotten" , "Airs, conceit" , "part" .)