Most tidy (7)
I believe the answer is:
neatest
'most tidy' is the definition.
('neat' can be a synonym of 'tidy')
This is the entire clue.
(Other definitions for neatest that I've seen before include "Seat ten (anag)" , "Most orderly" , "Most tidy" , "Most smart" , "best-looking desk, say?" .)