Better (10)
'better' is the definition.
(to ameliorate is to make better)
This is all the clue.
(Other definitions for ameliorate that I've seen before include "Become better" , "Make (something) better" , "seen to improve" , "Make (a bad thing) better" .)
'better' is the definition.
(I know that better can be written as improve)
This is the entire clue.
(Other definitions for improve that I've seen before include "Polish" , "Train" , "Make progress" , "pick up" , "Change for the better" .)