take the plunge

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take the plunge (third-person singular simple present takes the plunge, present participle taking the plunge, simple past took the plunge, past participle taken the plunge)

1. (idiomatic) To begin any major commitment.
   • 2009, Saras D. Sarasvathy, Effectuation: Elements of Entrepreneurial Expertise, page 196:

     And as scientists studying the subject, we will have to conclude that she will take the plunge only if she suffers from overconfidence bias or is innately risk-loving.

   • 2011 Allen Gregory, "1 Night in Gottlieb" (season 1, episode 2):

     Patrick: Joel and Brinique just went public with matching bracelets.

     Allen Gregory DeLongpre: Oh, he, uh, he took the plunge? Ahh, I know what that's like.

   • 2011, Jeffrey Runner, Experiments at the Interfaces, page ix:

     I decided to take the plunge as Series Editor by also taking the plunge as my first volume editor.

2. (idiomatic) To get engaged to be married.
   • 2001, Ben Young, Samuel Adams, The One: A Realistic Guide to Choosing Your Soul Mate:

     She's been seeing William now for about seven months and it looks as if they may take the plunge.

   • 2002, Judith Flanders, A Circle of Sisters:

     It was easier for Morris to take the plunge – he had an independent income and was wealthy enough to build a house in the country for himself and his wife.

   • 2007, Dr. David Gudgel, Brent Gudgel, Before You Get Engaged, page 203:

     I was pretty much going to be the last one among my peers to take the plunge. That meant I had previously heard their unique engagement stories.

   • 2012, Stephanie Bond, Stop the Wedding!::

     She shrugged. "I don't know. I guess I'm thinking who am I to tell my mother she shouldn't marry." “Especially since you're about to take the plunge yourself?” he asked lightly. She opened her mouth to tell him the truth, but the interest in his expression frightened her.

• jump in with both feet

• “take the plunge”, in Cambridge English Dictionary, Cambridge, Cambridgeshire: Cambridge University Press, 1999–present.
• “take the plunge” (US) / “take the plunge” (UK) in Macmillan English Dictionary.
• “take the plunge” in Longman Dictionary of Contemporary English, Longman.
• “take the plunge”, in Collins English Dictionary.
• “take the plunge”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.