More orderly (6)
I think it could be either:
'more orderly' is the definition.
('tidy' is associated in meaning with 'orderly')
This is all the clue.
(Other definitions for tidier that I've seen before include "not so disorderly" , "More trim" , "More neat and orderly" , "'Neater, in better order (6)'" , "straightened up?" .)
'more orderly' is the definition.
('neat' can be a synonym of 'orderly')
This is all the clue.
(Other definitions for neater that I've seen before include "More tidy and orderly" , "Less messy" , "Better" , "approaching apple-pie order" , "More spick and span" .)