assassin

From either French assassin or Italian assassino, from Arabic أَسَاسِيِّين (ʔasāsiyyīn, “people who are faithful to the foundation [of the faith]”) and the folkloric etymology Arabic حَشَّاشِين (ḥaššāšīn, “hashish users; low-lives”).

The mathematical sense was introduced by Bourbaki, playing on the notation Ass⁡(M) and the fact that an associated prime is the annihilator of an element, and so is said to kill that element.