Fruit — everyone buys it (5)
I believe the answer is:
olive
'fruit' is the definition.
(I know that olive is a type of fruit)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for olive that I've seen before include "Yellowish-green - fruit" , "Its branch is a peace emblem" , "Yellow-green colour like Mediterranean fruit" , "Fruit giving oil" , "Stoned fruit" .)