Straightens up (6)
'straightens up' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for neatens that I've seen before include "Tidies" , "Makes less 9" , "Cleans up" .)
(Other definitions for aligns that I've seen before include "Fits (with)" , "Joins forces" , "allies" , "Arranges in a straight row" , "Lines up" .)