1983 film drama starring Gene Hackman and Rutger Hauer (6)
I believe the answer is:
eureka
(Other definitions for eureka that I've seen before include "Archimedes' shout of triumph - re a uke (anag)" , "Cry on a great discovery" , "Excited cry after a discovery" , "alloy" , "Triumphant exclamation of discovery" .)