Crack in rotten, hollow fruit (4)
I believe the answer is:
rift
'crack' is the definition.
(rift is a kind of crack)
'rotten hollow fruit' is the wordplay.
'rotten' indicates an anagram.
'hollow' suggests removing the centre.
'fruit' with its middle taken out is 'frit'.
'frit' with letters rearranged gives 'RIFT'.
'in' is the link.
(Other definitions for rift that I've seen before include "opening" , "A disagreement or an earth cleft" , "Breach; crack" , "Breach in friendship or cleft in earth" , "Fissure; split" .)