Fruit gives staff energy (5)
I believe the answer is:
mango
'fruit' is the definition.
(type of fruit)
'staff energy' is the wordplay.
'staff' becomes 'man' (as in staffing or manning a particular place).
'energy' becomes 'go' (I've seen this in other clues).
'man'+'go'='MANGO'
'gives' acts as a link.
(Other definitions for mango that I've seen before include "fruit-tree" , "No, Mag has the odd fruit" , "Fruit, often in chutney" , "fruit tree" , "Tropical fruit, its pickle" .)