Children of Benjamin or Simeon (6)
I believe the answer is:
minors
'children' is the definition.
('minor' can be a synonym of 'child')
'of benjamin or simeon' is the wordplay.
'of' indicates the answer is hidden within the clue.
'MINORS' is hidden within 'benjamin or simeon'.
(Other definitions for minors that I've seen before include "They're too young to vote" , "Young people" , "could be little ones" , "They're under-age" , "They are legally under-age" .)