What connotation does the phrase 'go west' have? Where did this originate?

''GO WEST'' meanings: a) In British English, the primary meaning of to go west is to die; this phrase later came to also mean: - to be lost, to be destroyed; - to disappear, to vanish; - to end in failure, to come to grief. b) When something goes west, it stops existing or working. c) lost, damages, or spoiled in some way d) be killed or lost; meet with disaster. d) 19c British idiom for ''die, be killed'' (popularized during World War I), probably from thieves' slang, wherein to go west meant to go to Tyburn, hence to be hanged, though the phrase has indubitably been influenced by the setting of the sun in the west''.