A hollow nut found in ordinary fruit (8)
I believe the answer is:
plantain
'fruit' is the definition.
(thesaurus)
'a hollow nut found in ordinary' is the wordplay.
'hollow' says to hollow out the word (remove centre letters).
'found in' indicates putting letters inside.
'ordinary' becomes 'plain' (I've seen this before).
'nut' with its centre removed is 'nt'.
'a'+'nt'='ant'
'ant' placed into 'plain' is 'PLANTAIN'.
(Other definitions for plantain that I've seen before include "Coarse banana" , "Banana-like fruit" , "Pal at inn (anag)" , "Tropical plant like a banana" , "Green-skinned banana" .)