Sole member of citrus family (5)
I believe the answer is:
lemon
'sole' is the definition.
(lemon sole is a kind of sole)
'member of citrus family' is the wordplay.
I cannot really see how this works, but
'member' could be 'm' (political abbreviation) and 'm' is located in the answer.
'of' could be 'o' and 'o' is found within the answer.
The remaining letters 'len' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for lemon that I've seen before include "Leaving body" , "Sharp-tasting fruit" , "Feeble thing (colloq.); fruit tree" , "very different from peach?" , "Melon is another fruit" .)