Rest concerned with malice (7)
I believe the answer is:
respite
'rest' is the definition.
(I know that rest can be written as respite)
'concerned with malice' is the wordplay.
'concerned with' becomes 're' (re can mean regarding, concerning).
'malice' becomes 'spite' (spite is a kind of malice).
're'+'spite'='RESPITE'
(Other definitions for respite that I've seen before include "Pause from pain" , "Short let-up" , "Abatement, rest" , "Relaxation" , "Period of relief (from unpleasant thing)" .)