Men of the future (4)
I believe the answer is:
boys
'men' is the definition.
(I have seen 'Young men ' mean 'boys' so perhaps 'men' could also mean 'boys')
'of the future' is the wordplay.
I cannot really see how this works, but
'of' could be 'o' and 'o' is found within the answer.
The remaining letters 'bys' 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 boys that I've seen before include "They will be themselves, it's said" , "Lads" , "Male children" , "Beach --, group" , "Young men" .)