Malaise of Leftie evident in roar (7)
I believe the answer is:
boredom
'malaise' is the definition.
(thesaurus)
'leftie evident in roar' is the wordplay.
'leftie' becomes 'red' (I've seen this in other clues).
'evident in' means one lot of letters goes inside another.
'roar' becomes 'boom' ('boom' can be a synonym of 'roar').
'red' inserted inside 'boom' is 'BOREDOM'.
'of' is the link.
(Other definitions for boredom that I've seen before include "Feeling" , "Monotony" , "Overseers" , "weary idleness" , "Ennui in bedroom" .)