Set right line up when cutting grass (9)
I believe the answer is:
redressed
'set right' is the definition.
(I've seen this in another clue)
'line up when cutting grass' is the wordplay.
'line up' becomes 'dress' (synonyms).
'when cutting' means one lot of letters goes inside another (some letters cut their way into a word).
'grass' becomes 'reed' (type of grass plant).
'dress' going into 'reed' is 'REDRESSED'.
(Other definitions for redressed that I've seen before include "Given compensation" , "Compensated" , "put right" , "Set right, often the balance" , "Made amends" .)