Grown-up boys (3)
I believe the answer is:
men
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">grown-up boys</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for men that I've seen before include "Adult males" , "Crew" , "Human males" , "Fellows, chaps" , "- - -o'-war (ships)" .)