twenty-minute egg

plural twenty-minute eggs

1. datedslangA very hard-boiled person; one who is tough and unsentimental

   He was a twenty-minute egg, according to your grandfather, and such men are not soon forgotten.

   1932, Peter B. Kyne, Lord of Lonely Valley

   2 more examples

   The delegates to a national convention are, as the politicians say, "twenty-minute eggs," and such a convention is the super-market place for political deals and bargains, trades and treachery.

   1938, Frank Richardson Kent, The great game of politics, page 246

   'A stinker?' No, he said, it wasn't a stinker. 'A tough baby?' 'No.' 'A twenty-minute egg?' 'That was it, sir. Mr Runkle is a twenty-minute egg.'

   1971, Pelham Grenville Wodehouse, Much obliged, Jeeves