insidiator

Etymology

From Latin īnsidiātor.

insidiator means someone who lies in ambush, or plots. Lexicurio rates it Sui generis — a strength score of 87 out of 100.

Why this word is great

INSIDIATOR — [Noun] One who lies in ambush or schemes with treacherous intent. From the Latin insidiator ("one who lies in wait, ambusher"), from insidiae ("ambush, plot, snare"). Unlike an "adversary," who confronts in the open field, or a "conspirator," who whispers in collaborative dark, the insidiator is defined by a patient, solitary calculus of the trap. It is the figure motionless in the forest bracken, the unopened letter containing a calibrated lie, the floorboard that gives way only under a trusted footstep—the architecture of betrayal built to look like the world.

noun

Someone who lies in ambush, or plots“many both open enemies and close insidiators; from whose force or treachery no human providence can sufficiently guard them”