Fruit alone displays different core (4)
I believe the answer is:
sloe
'fruit' is the definition.
(I know that sloe is a type of fruit)
'alone displays different core' is the wordplay.
'alone displays' becomes 'slo' (I can't explain this - if you can you should give a lot more credence to this answer).
'different' becomes 'new' (similar in meaning).
'core' means to look at the middle letters.
The middle letter of 'new' is 'e'.
'slo'+'e'='SLOE'
Can you help me to learn more?
(Other definitions for sloe that I've seen before include "Fruit of the blackthorn does't sound fast" , "Black fruit" , "Thorny bush with plum-like fruit" , "Sour blue-black fruit" , "Wild plum" .)