Horrible-looking fruit, I hear (4)
I believe the answer is:
ugly
'horrible-looking' is the definition.
(ugly means horrible to look at)
'fruit i hear' is the wordplay.
'fruit' becomes 'ugli' (ugli is a kind of fruit).
'i hear' shows a homophone (sound like).
'ugli' sounds like 'UGLY'.
(Other definitions for ugly that I've seen before include "Deficient in beauty" , "Unpleasant to look at" , "Like an eyesore" , "'Unattractive, unsightly (4)'" , "Unsightly, not pretty" .)