Seed in ripe apple (3)
I believe the answer is:
pea
'seed' is the definition.
(I've seen this before)
'in ripe apple' is the wordplay.
'in' indicates the answer is hidden within the clue.
'PEA' can be found hidden inside 'ripe apple'.
(Other definitions for pea that I've seen before include "Spherical vegetable" , "Edible green seed" , "Small vegetable" , "It may climb frame" , "Edible seed from pod" .)