Fleshy fruit will give a chap vigour (5)
I believe the answer is:
mango
'fleshy fruit' is the definition.
(I know that mango is a type of drupe)
'give a chap vigour' is the wordplay.
'give' means one lot of letters go next to another.
'a chap' becomes 'man' (chap can mean a man).
'vigour' becomes 'go' (go can mean energy or vigour).
'man' put next to 'go' is 'MANGO'.
'will' acts as a link.
(Other definitions for mango that I've seen before include "Tropical fruit, its pickle" , "Once exotic fruit" , "Large oval tropical fruit" , "Asian fruit" , "Ovoid edible fruit" .)