Set fault out as fastidious (8)
I believe the answer is:
tasteful
'fastidious' is the definition.
(thesaurus)
'set fault out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'set'+'fault'='setfault'
'setfault' with letters rearranged gives 'TASTEFUL'.
'as' acts as a link.
(Other definitions for tasteful that I've seen before include "Let Faust have ability to enjoy good things" , "Free of tawdriness" , "Showing discernment" , "Showing good aesthetic judgement" , "Decorous" .)