Splendid, wonderful (6)
I believe the answer is:
superb
I believe this is a double definition.
'splendid' is the first definition.
(both can mean excellent)
'wonderful' is the second definition.
(I've seen this before)
(Other definitions for superb that I've seen before include "Splendid, marvellous" , "fine" , "First-class" , "Quite splendid, really excellent" , "Triumphantly effective" .)