Less old (7)

I believe the answer is:
younger
'less old' is the definition.
('young' can be the opposite of 'old' so perhaps 'younger' is reasonable for 'less old')
This is all the clue.
(Other definitions for younger that I've seen before include "More juvenile" , "Comparatively raw" , "Less mature" , "more boyish" , "More immature" .)