when Hell freezes over
bijwoord
Roget 107: never, ne'er [Contr.]; at no time, at no period; on the second Tuesday of the week, when Hell freezes over; on no occasion, never in all one's born days, nevermore, sine die; in no degree.
Vind elders meer over when Hell freezes over: etymologie - rijmwoorden - Wikipedia.
debug info: 0.1207