Pronunciation: (u-sas'in), [key]
1. a murderer, esp. one who kills a politically prominent person for fanatical or monetary reasons.
2. (cap.) one of an order of Muslim fanatics, active in Persia and Syria from about 1090 to 1272, whose chief object was to assassinate Crusaders.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.