1 literary die, especially in a violent or sudden way:a great part of his army perished of hunger and disease
suffer complete ruin or destruction:must these noble hopes perish so soon?
2(of rubber, food, etc.) lose its normal qualities; rot or decay:an abandoned tyre whose rubber had perished
3 (be perished) British informal be suffering from extreme cold:I was perished with cold before the end of the day
perish the thought
informal used, often ironically, to show that one finds a suggestion or idea completely ridiculous or unwelcome:he wasn’t out to get drunk—perish the thought!