Tidies leaderless canteens in disarray (7)
I believe the answer is:
neatens
'tidies' is the definition.
('neaten' can be a synonym of 'tidy')
'leaderless canteens in disarray' is the wordplay.
'leaderless' means to remove the first letter.
'in disarray' indicates an anagram.
'canteens' with its initial letter removed is 'anteens'.
'anteens' with letters rearranged gives 'NEATENS'.
(Other definitions for neatens that I've seen before include "Tidies" , "Cleans up" , "Makes less 9" .)