Sorceress jilted by Jason (5)
I believe the answer is:
medea
'sorceress jilted by jason' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for medea that I've seen before include "Sorceress involved with Jason" , "Tragic heroine" , "In Greek myth, Jason's wife who killed their children in jealous rage" , "Jason's sorceress" , "Jason's wife who murdered their children" .)