Improve meal or I eat out (10)
I believe the answer is:
ameliorate
'improve' is the definition.
(synonyms)
'meal or i eat out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'meal'+'or'+'i'+'eat'='mealorieat'
'mealorieat' with letters rearranged gives 'AMELIORATE'.
(Other definitions for ameliorate that I've seen before include "Become better" , "Make (something) better" , "Make (a bad thing) better" , "seen to improve" .)