Plunge | Webster's Dictionary (1865)

Plŭnge, v. t.

verbtransitive

v. t. [imp. & p. p. PLUNGED; p. pr. & vb. n. PLUNGING.] [Fr. plonger, from Lat. as if plumbicare, from plumbum, lead; Fr. plomber, to plumb and plunge, It. piombare, to fall down perpendicularly, equivalent to cadere a piombo.]

To thrust into water or other fluid substance, or into any substance that is penetrable; to immerse in a fluid; to drive into flesh, mire, earth, or the like; as, to plunge the body in water.
Hence, to thrust or drive into any state so as to be enveloped or surrounded; to overwhelm; to embarrass. [Obs.] “Plunged and graveled with three lines of Seneca.” Browne.
To baptize by immersion.

Plŭnge, v. i.

verbintransitive

v. i. 1. To thrust or drive one's self into water, or a fluid; to dive, or to rush in; to pitch; as, he plunged into the river.

His courser plunged, And threw him off; the waves whelmed over him. Dryden.

Sense 2. To fall or rush, as into distress, or any state or circumstances in which the person or thing is enveloped, inclosed, or overwhelmed; as, to plunge into debt or embarrassments.

Sense 3. To pitch or throw one's self headlong, as a horse.

Plŭnge, n.

noun

n. 1. The act of thrusting into water or any penetrable substance.

Sense 2. A state of being surrounded or overwhelmed with difficulties; difficulty; strait; distress. [Rare.]

And wilt thou not reach out a friendly arm To raise me from amidst this plunge of sorrow? Addison.

Sense 3. The act of pitching or throwing one's self headlong, like an unruly horse.