Genteel umpire will dine out (7)
I believe the answer is:
refined
'genteel' is the definition.
(similar in meaning)
'umpire will dine out' is the wordplay.
'umpire' becomes 'ref' (short for referee).
'will' says to put letters next to each other (I've seen this in other clues).
'out' indicates an anagram (out can mean wrong or inaccurate).
'dine' anagrammed gives 'ined'.
'ref'+'ined'='REFINED'
(Other definitions for refined that I've seen before include "Freed from impurities by processing" , "Just like the cultured" , "Discerning" , "With impurities removed" , "Not coarse" .)