means A long-barreled firearm with spiral grooves cut inside the bore to spin the bullet for accuracy over distance (or, as a verb, to ransack a place or steal).

from From the verb 'rifle' meaning to grasp, plunder, or search through — borrowed from Old French 'rifler' (to scratch, scrape, or strip bare), of Germanic origin and possibly related to words for tearing or grazing. The gun sense grew from a separate but related notion: the spiral grooves are 'rifling,' from the same idea of scratching or scoring a surface. So the weapon is literally named for the gouges raked into its barrel — and shares deep roots with the act of ransacking.