Old boarding (7,2)
I believe the answer is:
getting on
I believe this is a double definition.
'old' is the first definition.
(thesaurus)
'boarding' is the second definition.
('get on' can be a synonym of 'board')
(Other definitions for getting on that I've seen before include "Elderly; succeeding" , "doing well" , "Enjoying friendly relations" , "as a boarder > in later years?" , "Being successful" .)