Tidy part of scene at engagement (6)
I believe the answer is:
neaten
'tidy' is the definition.
('neaten' can be a synonym of 'tidy')
'part of scene at engagement' is the wordplay.
'part of' indicates the answer is hidden within the clue.
'NEATEN' is hidden in the letters of 'scene at engagement'.
(Other definitions for neaten that I've seen before include "Trim" , "Spruce up" , "Straighten up" , "Groom" , "set in order" .)