Jason jilted her (5)
I believe the answer is:
medea
'jason jilted her' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for medea that I've seen before include "Greek sorceress" , "Tragedy by Euripedes" , "Tragic heroine" , "Greek princess who helped Jason get the Golden Fleece" , "Jason's wife who murdered their children" .)