(UK, Australia) Cease to boil when heat is no longer applied. / (idiomatic, UK, Australia) To lose interest; to pall. / (idiomatic, UK, Australia) To become of diminished intensity or urgency.

Alternative spelling of go pear-shaped

Ireland forever.

(US) hide and seek

(idiomatic) To fail. / (idiomatic) To degenerate rapidly.

(idiomatic) Of a horse, to break suddenly into a gallop. / (idiomatic) Suddenly to say or do something impetuous.

(dated) go away (and stop bothering me)

To challenge someone.

(Cockney rhyming slang) To go wrong.

To say that somebody is not to do anything without receiving further instructions. / To say that somebody is obliged to do something without question.