Its leaf serves a modest purpose (3)
I believe the answer is:
fig
'purpose' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for fig that I've seen before include "something unimportant" , "Fruit full of tiny seeds" , "This leaf may conceal nudity in art" , "Fruit with lots of seeds" , "Soft pear-shaped fruit" .)