to thrust into water, or into any substance that is penetrable; to immerse; to cause to penetrate or enter quickly and forcibly; to thrust; as, to plunge the body into water; to plunge a dagger into the breast.  also used figuratively; as, to plunge a nation into war.-to baptize by immersion.-to entangle; to embarrass; to overcome.-to thrust or cast one's self into water or other fluid; to submerge one's self; to dive, or to rush in; as, he plunged into the river. also used figuratively; as, to plunge into debt.-to pitch or throw one's self headlong or violently forward, as a horse does.-to bet heavily and with seeming recklessness on a race, or other contest; in an extended sense, to risk large sums in hazardous speculations.-the act of thrusting into or submerging; a dive, leap, rush, or pitch into, or as into, water; as, to take the water with a plunge.-hence, a desperate hazard or act; a state of being submerged or overwhelmed with difficulties.-the act of pitching or throwing one's self headlong or violently forward, like an unruly horse.-heavy and reckless betting in horse racing; hazardous speculation.