One ignored by unkind older boys (3)
I believe the answer is:
men
'older boys' is the definition.
The answer and definition can be both people as well as being plural nouns.
Perhaps they are linked in a way I don't understand?
'one ignored by unkind' is the wordplay.
'one' becomes 'a' (a thing is one thing).
'ignored by' indicates named letters should be taken away.
'unkind' becomes 'mean' (I've seen this before).
'mean' with 'a' taken out is 'MEN'.
Can you help me to learn more?
(Other definitions for men that I've seen before include "Chess pieces" , "Male humans" , "gents" , "Human males" , "'So many ..., so many opinions'" .)