From the time death struck Jason's first wife (5)
I believe the answer is:
medea
'jason's first wife' is the definition.
(I've seen this in another clue)
'from the time death struck' is the wordplay.
'from' indicates a hidden word.
'MEDEA' is hidden in the letters of 'time death struck'.
(Other definitions for medea that I've seen before include "Greek princess who helped Jason obtain the Golden Fleece" , "fabulous princess" , "Sorceress who helped Jason get the Golden Fleece" , "In Greek myth, Jason's wife who killed their children in jealous rage" , "Play by Euripides" .)