Grit ruined red outfit (9)
I believe the answer is:
fortitude
'grit' is the definition.
(thesaurus)
'ruined red outfit' is the wordplay.
'ruined' indicates anagramming the letters.
'red'+'outfit'='redoutfit'
'redoutfit' anagrammed gives 'FORTITUDE'.
(Other definitions for fortitude that I've seen before include "Bravery" , "Courage in bearing pain or trouble" , "Mental and emotional strength" , "Enduring courage" , "Red outfit for courage" .)