Make up nothing in neat fashion (5)
I believe the answer is:
atone
'make up' is the definition.
(to atone for something is to make up for it)
'nothing in neat fashion' is the wordplay.
'nothing' becomes 'O' (looks like zero - 0).
'in' is an insertion indicator.
'fashion' indicates anagramming the letters.
'neat' is an anagram of 'atne'.
'o' inserted within 'atne' is 'ATONE'.
(Other definitions for atone that I've seen before include "Make up for wrong done" , "Make up, compensate (for)" , "Recompense" , "Make good" , "Adopt a cause" .)