Most neat bird conceals wounded side (7)
I believe the answer is:
tidiest
'most neat' is the definition.
('tidy' can be a synonym of 'neat')
'bird conceals wounded side' is the wordplay.
'bird' becomes 'tit' (I've seen this before**).
'conceals' is an insertion indicator.
'wounded' indicates anagramming the letters (I've seen this in other clues).
'side' anagrammed gives 'dies'.
'tit' going around 'dies' is 'TIDIEST'.
(Other definitions for tidiest that I've seen before include "One orderly more than others" , "most trim" , "smarter than anything" , "optimally arranged" , "Extremely organised" .)