Gets on (6)
'gets on' is the definition.
(get on can mean to get older)
This is all the clue.
(Other definitions for ages that I've seen before include "Long periods" , "Historical eras" , "Yonks" , "A long time (colloq.)" , "Awfully long time" .)
'gets on' is the definition.
('board' can be a synonym of 'get on')
This is the entire clue.
(Other definitions for boards that I've seen before include "Long flat pieces of wood" , "Puts up" , "Committees or planks" , "Tread them in the theatre" , "Goes on" .)