jump off the deep end

jump off the deep end

1. Literally, to jump into the deep end of a pool (as opposed to the shallow end). Don't let Sally jump off the deep end—she doesn’t know how to swim.
2. To become crazy, frenzied, or irrational. A: "Now your father thinks the neighbors are plotting against him." B: "Wow, he really jumped off the deep end, huh?" Whoa, man, stop yelling! I only put a tiny scratch on your car—no need to jump off the deep end.
3. To begin doing something very complex, overwhelming, or unfamiliar, especially suddenly and without guidance, assistance, or preparation. I'm a little nervous about starting my graduate degree program, but I'm determined to jump off the deep end and give it a go. Those who go the furthest in life are the ones willing to jump off the deep end when a great opportunity arises.
See also: deep, end, jump, off
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

jump off the deep end (over someone or something)

Fig. to get deeply involved with someone or something. (Often refers to romantic involvement.) Jim is about to jump off the deep end over Jane. Jane is great, but there is no need for Jim to jump off the deep end.
See also: deep, end, jump, off
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
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