Fruit of which there's a bad loss out East (5)
I believe the answer is:
sloes
'fruit of which' is the definition.
Although both the answer and 'fruit' are nouns, they are not in the same form of the noun.
'a bad loss out east' is the wordplay.
'a bad' indicates an anagram.
'out' is an insertion indicator.
'east' becomes 'e' (synonyms).
'loss' is an anagram of 'slos'.
'slos' going around 'e' is 'SLOES'.
'there's' acts as a link.
Can you help me to learn more?
(Another definition for sloes that I've seen is " Fruit of the blackthorn".)