WNBA official (7)
'wnba official' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ref that I've seen before include "Football's whistler" , "Football official (colloq.)" , "A diminutive umpire in soccer or boxing" , "Sports official (abbrev.)" , "In brief, a soccer controller" .)
(Other definitions for referee that I've seen before include "Sporting arbitrator" , "Official who ensures fair play" , "Game official" , "Match official" , "Arbiter" .)