c. 1600 (transitive), from French submerger (14c.) or directly from Latin submergere "to plunge under, sink, overwhelm," from sub "under" (see sub-) + mergere "to plunge, immerse" (see merge). Intransitive meaning "sink under water, sink out of sight" is from 1650s, made common 20c. in connection with submarines. Related: Submerged; submerging.
early 15c., "suffocation by being plunged into water," from Late Latin submersionem (nominative submersio) "a sinking, submerging," noun of action from past participle stem of submergere "to sink" (see submerge). General sense from early 17c.
"to plunge into (a fluid)," early 15c. (implied in immersed), from Latin immersus, past participle of immergere "to plunge in, dip into, sink, submerge" (see immersion). Figuratively, of study, work, passion, etc., from 1660s. Related: Immersed; immersing; immersive.
c. 1200, "to submerge, sink; drown, kill by drowning," from Old English drencan "give drink to, ply with drink, make drunk; soak, saturate; submerge, drown," causative of drincan "to drink" (see drink (v.)), from Proto-Germanic *drankijan (source also of Old Norse drekkja, Swedish dränka, Dutch drenken, German tränken, Gothic dragkjan "to give to drink").
The sense of "to wet thoroughly by throwing liquid over" is by 1550s. For similar causal pairs, compare stink and stench, cling and clench, shrink and Middle English shrench "cause to shrink." Related: Drenched; drenching.
mid-14c., overwhelmen, "to turn upside down, overthrow, knock over," from over- + Middle English whelmen "to turn upside down" (see whelm). Meaning "to submerge completely" is early 15c. Perhaps the connecting notion is a boat, etc., washed over, and overset, by a big wave. Figurative sense of "to bring to ruin" is attested from 1520s. Related: Overwhelmed; overwhelming; overwhelmingly.
early 14c. "to send to the bottom" (transitive); late 14c., "to sink or fall" (intransitive), from Old French fondrer "collapse; submerge, sink, fall to the bottom" (Modern French fondrier), from fond "bottom" (12c.), from Latin fundus "bottom, foundation" (see fund (n.)). Not especially of ships in Middle English, where it typically meant "fall to the ground." Figurative use from 1580s. Related: Foundered; foundering.
c. 1500, from Late Latin immersionem (nominative immersio), noun of action from past participle stem of immergere "to plunge in, dip into, sink, submerge," from assimilated form of in- "into, in, on, upon" (from PIE root *en "in") + Latin mergere "plunge, dip" (see merge). Meaning "absorption in some interest or situation" is from 1640s. As a method of teaching a foreign language, 1965, trademarked by the Berlitz company.
late 14c., plungen, "to put, throw, or thrust violently into; immerse, submerge," also intransitive, from Old French plongier "plunge, sink into; plunge into, dive in" (mid-12c., Modern French plonger), from Vulgar Latin *plumbicare "to heave the lead," from Latin plumbum "lead" (see plumb (n.)). Original notion perhaps is of a sounding lead or a fishing net weighted with lead. Figurative sense of "cast into some state or condition" (despair, etc.) is from late 14c. Related: Plunged; plunging. Plunging neckline in women's fashion is attested from 1949.