sam·u·rai 
(sămə-rī′)
(sămə-rī′)n. pl. samurai or sam·u·rais
1. The Japanese feudal military aristocracy.
2. A professional warrior belonging to this class.
[Japanese, warrior, from Old Japanese samurafi : sa-, pref. of unknown meaning + morafi, to watch, frequentative of mor-, to guard.]