Smart role-casting in “Peppery” (8)
I believe the answer is:
choleric
'peppery' is the definition.
(thesaurus)
'smart role-casting in' is the wordplay.
'smart' becomes 'chic' ('chic' can be a synonym of 'smart'**).
'casting' is an anagram indicator.
'in' means one lot of letters goes inside another.
'role' with letters rearranged gives 'oler'.
'chic' enclosing 'oler' is 'CHOLERIC'.
(Other definitions for choleric that I've seen before include "Of angry disposition, cliche or what?" , "Irascible" , "Annoyed" , "Hot-tempered" , "Ill-tempered" .)