off the deep end

off the deep end

slang Crazy or irrational. A; "Now your father thinks the neighbors are plotting against him." B: "Wow, he's really gone off the deep end!" Whoa, man, stop yelling! I only put a tiny scratch on your car, so there's no need to go off the deep end.
See also: deep, end, off
Farlex Dictionary of Idioms.

off the deep end, to go

To overreact; to let one’s emotions carry one away. The “deep end” presumably means the deep water at the end of a swimming pool, which it is rash to enter unless one can swim. The term became current in the early twentieth century. “There’s no reason for your going off the deep end,” wrote Kathleen Knight (Rendezvous with the Past, 1940).
See also: deep, go, off
The Dictionary of Clichés by Christine Ammer
See also:
  • off the deep end, to go
  • double buffalo
  • from go to whoa
  • take things easy
  • take it easy
  • take it/things easy
  • from giddy-up to whoa
  • dudical
  • not so fast
  • break it up
References in periodicals archive
The Gunny said the three magic words that will send any woman off the deep end, not to mention a psychopath, "Honey, Calm Down!" No sooner had the words left his mouth then Wooosh, every stitch of clothing he owned was ablaze.
Duck Crazy: It is in the genes of every waterfowler's spouse
When faced with a decision, you're more likely to jump off the deep end today.
YOUR HOROSCOPE WITH
Instead, we should act like biologists, poking and prodding them and hoping that we can understand just enough to get the system to do what we want without going off the deep end of radical misbehavior.
Is Technology Getting Too Complicated?
Many people do not realize that this election is the turning point for America: We could go off the deep end into socialism or create laws degrading our Republic and its principles.
What the future holds
Consider this from Shift, describing the situation when he started the transformation of the ailing Renault: "Some people said, 'He's off the deep end. He's raving mad.
Carlos Ghosn and results
Britain's Horror Homes, It's Not Rocket Science, Shop Well For Less, C5's Trauma Doctors, Troubled Teens: Jail Shock on CBS Reality and "people spending too much money on swimming pools" on Animal Planet's Insane Pools: Off The Deep End.
Runaway Hound
So why do I say that only one party has gone off the deep end?
How America Was Lost
What if I did go off the deep end? So, before you are knees and with your Joe "You've all seen those films about stars who go off the deep end and you watch them explode and fall to the ground.
WILD strings; Guitar hero Joe Satriani is loved for living it large on the stage - but he'll never take this crazy guy persona home with him. Michael Wood reports
What if I did go off the deep end? "You've all seen those films about stars who go off the deep end and you watch them explode and fall to the ground.
Wild man on stage, ordinary Joe off it; Guitar hero Joe Satriani is loved for living it large on the world stage - but he'll never take this crazy guy persona home with him. Michael Wood reports
Last season's Insane Pools: Off the Deep End chronicled Congdon and his colorful crew's efforts to build ever-more-outrageous outdoor spaces for Southwest Florida clients, moving mountains of dirt and tons of boulders while battling heat, nerves and looming deadlines.
One day: with Lucas Gongdon of Lucas Lagoons
Driving an already unbalanced head of state off the deep end is clearly not something diplomats should sign off on.
North Korea: An 'act of war' over a movie?
during that pause, was For a few seconds, Saints fans probably thought their chairman had gone off the deep end and I'm sure the ensuing laughter on the Sky TV set was replicated on sofas throughout the land.
NO JOKES IN FACING DRAGONS; Saints chairman brought humour to ClubCall process but there was only going to be one option for the semi finals St Helens
One such person is former best friend Benny Friedman, who has clearly gone off the deep end. Obsessed with the JFK assassination, he insists he has evidence that Oswald wasn't acting alone.
When the Past Came Calling
Here are seven tips to try before you end up shooting yourself in the foot, going off the deep end, or doing irreparable harm to your relationship, reputation and career.
7 Tips to Manage Your Boss - Yourself
"We have listened to the people of Saltburn but a small minority of people have gone totally off the deep end," he said.
Plea over parking; Protesters hand over petition