Assassin

Vine's Expository Dictionary of NT Words

1: Σικάριος (Strong'S #4607 — Noun Masculine — sikarios — sik-ar'-ee-os )

is a Latin word (sicarius, "from" sica, "a dagger") denoting "one who carries a dagger or short sword under his clothing, an assassin,"  Acts 21:38 , RV. Here it is used as a proper name (see the RV) of the Sicarii, "assassins," the fanatical Jewish faction which arose in Judea after Felix had rid the country of the robbers referred to by Josephus (Ant., XX). They mingled with the crowds at festivals and stabbed their political opponents unobserved (AV, "murderers").

Webster's Dictionary

(1): (n.) One who kills, or attempts to kill, by surprise or secret assault; one who treacherously murders any one unprepared for defense.

(2): (v. t.) To assassinate.