assassin (n.)
An assassin kills someone prominent, usually for political reasons. The word came into European languages from variants of the Arabic hashishi, plural hashishiyya.1
It was not a description. Other Muslims used it against the Nizari Ismailis as an insult, in the sense of low-class rabble or people of lax morals, with no claim attached that they used the drug.1
The literal reading came later, and from outside. Crusader-era reports and then Marco Polo told of an Old Man of the Mountain who drugged young men and showed them a garden of paradise so they would kill on command. Farhad Daftary’s work on those accounts traces them to European invention and rumour rather than to anything recorded at Alamut.12
The legend crossed into English and took the word with it. The drug is still in the name, and nobody has been able to show it was ever there.12
He was killed by an assassin.