Excellent group of directors? Right! (9)
I believe the answer is:
starboard
'right' is the definition.
(right side of a ship)
'excellent group of directors?' is the wordplay.
'excellent' becomes 'star' (star can mean excellent or top-quality).
'group of directors?' becomes 'board' (board of directors).
'star'+'board'='STARBOARD'
(Other definitions for starboard that I've seen before include "right to 14 [YACHTS]" , "Right-hand side of ship while facing forward" , "One side of a ship" , "Right side at sea" , "Literally, the steering side of a vessel" .)