Choice, highly desirable (4)
I believe the answer is:
plum
This clue is a double definition.
'choice' is the first definition.
(both can mean excellent)
'highly desirable' is the second definition.
(plum can mean excellent)
(Other definitions for plum that I've seen before include "Fruit tree - of especial value?" , "Best; fruit" , "Oval fruit with single hard stone" , "Dark bluish-red - fruit" , "Dark reddish-purple colour: especially valued" .)