take the plunge
idiomatic phrase

- to begin an unfamiliar venture, especially after hesitating

- to decide to do something important or risky, especially after thinking about it for a long time

The American Heritage Dictionary / The Longman Dictionary

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PHRASE ORIGIN

The late 14th century verb plungen, meaning “to put, throw, or thrust violently into; to immerse, submerge”, can be traced back to the Latin plumbum, meaning “lead”. This may be connected to a depth-sounding lead or a fishing net weighted with lead.

The noun form of "plunge", from around 1400, meant “a deep pool".

The figurative use in “take the plunge” (to commit oneself) is well established by 1823. The exact phrase might owe its popularity to its appearance in the widely read “The Vicar of Wakefield” (1766):

“Mr. Thornhill’s assurance had entirely forsaken him: he now saw the gulph of infamy and want before him, and trembled to take the plunge. He therefore fell on his knees before his uncle, and in a voice of piercing misery implored compassion.”

Btw, the adjective form in the phrase “plunging neckline” in women’s fashion is attested from 1949.

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HE TOOK THE PLUNGE TOO FAR !

The noted evolutionary biologist W. D. (Bill) Hamilton, who met an untimely death after a collecting expedition to the Congo in 2000, made it his practise to plunge his hand down any hole in the jungle floor to discover what might be lurking there.

Hamilton had indeed lost the tips of several fingers on his right hand, but this was the result of a childhood experiment with explosives.

Whenever he came upon an insect nest, Hamilton would beat at it with a stick to see what emerged. Hamilton’s obituarist reports that he saw Hamilton run away only once — after he had disturbed a hive of killer bees.

From The Oxford Book of Scientific Anecdotes

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SYNONYMS

- to commit oneself to a task or decision, typically one that involves risk:

bet the farm, bet the ranch, bite the bullet, commit (oneself), cross the Rubicon, dive in, face the music, go for it, grasp the nettle, jump in (at the deep end), just do it, leap into the breach, plunge in, seize the opportunity, show your mettle, take the bull by the horns, take the initiative, TAKE THE PLUNGE, throw caution to the wind(s)

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BEFORE YOU GO

Note that the verb “to plunge” has two main meanings:

(1)  to throw something or oneself into a substance or place, typically with force, as in:

- He plunged into the pool with a big splash.

- The dogs plunged into the forest undergrowth.

- Full of enthusiasm, she plunged headfirst into her new job.

(2) to become lower in value or level very suddenly and quickly, as in:

- "Twitter Shares Plunge After Elon Musk Backs Away From $44B Deal"

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SMUGGLE OWAD into an English conversation, say something like:

“Selena finally TOOK THE PLUNGE and set up her own business.”

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THANKS to Dirk for suggesting today’s OWAD.

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