n. One of the Assassins, a military and religious order in Syria, founded in Persia by Hassan ben Sabbah about the year 1090.n. One who undertakes, for a reward previously agreed on, to put another person to death by surprise or secret assault; hence, one who kills, or attempts to kill, by treacherous violence; a murderer.n. A breast-knot, or similar decoration worn in front.To murder; assassinate.