Go off the deep end
Meaning
To lose emotional or mental control, often resulting in irrational or extreme behavior.
Origin
In the bustling public swimming pools of early 20th-century America, the "deep end" was a specific, often perilous zone, a sharp drop-off from the shallower waters where most people felt safe. For a swimmer, particularly one not entirely confident, to literally "go off the deep end" meant to venture suddenly into the overwhelming depths, risking panic, thrashing, and a desperate struggle to stay afloat. This vivid image of a swimmer losing control in the water quickly migrated into common speech, becoming a powerful metaphor for someone suddenly losing their emotional or mental composure, plunging headfirst into irrationality or extreme behavior, much like a person flailing beyond their capabilities in the literal deep end.
Examples
- After weeks of relentless stress, he finally went off the deep end and started yelling at his colleagues for minor issues.
- She worried her grandmother might go off the deep end if she heard the news about the house sale.