Malice surrounding river spirit (6)
I believe the answer is:
sprite
'spirit' is the definition.
(thesaurus)
'malice surrounding river' is the wordplay.
'malice' becomes 'spite' (synonyms).
'surrounding' indicates putting letters inside.
'river' becomes 'r' (abbreviation for river).
'spite' enclosing 'r' is 'SPRITE'.
(Other definitions for sprite that I've seen before include "Impish type" , "water pixie" , "Supernatural being" , "Pet, sir, could be a goblin" , "Stripe on a fairy" .)