off the deep end

adj — 2 senses

off the deep end

adj

1

Extremely angry.

Usually in the phrase 'go off the deep end'

I told him that I'd broken the vase, and he went off the deep end.

2

US, Idiomatic Crazy, erratic, or irrational.

It used to be a funny comic, but lately it has gone off the deep end.
I lost a good friend / Christmastime when folks go off the deep end / His woman took the kids and he took Klonopin / Enough to kill a man of twice his size2013, Jason Isbell, “Relatively Easy”, in Southeastern:

Related terms: off the wall

Entry derived from the Wiktionary, under licence CC BY-SA 4.0 — list of authors.