Men of tomorrow (4)
I believe the answer is:
boys
'men of tomorrow' is the definition.
(I've seen this in another clue)
'men of' is the wordplay.
I cannot quite understand how this works, but
'of' could be 'o' and 'o' is found in the answer.
The remaining letters 'bys' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for boys that I've seen before include "Male children" , "Young males" , "Lads" , "Beach --, group" , "They will be themselves, it's said" .)