mayn't

past mightn't

1. archaicno past participleno present participlemay not (negative auxiliary)

   "Yes, we went to school in the sea, though you mayn't believe it—"

   1865 November (indicated as 1866), Lewis Carroll [pseudonym; Charles Lutwidge Dodgson], “The Mock Turtle’s Story”, in Alice’s Adventures in Wonderland, London: Macmillan and Co., →OCLC, page 142

   4 more examples

   I mayn't have much head, master, but I’ve head enough to remember those that use me ill.

   1841 February–November, Charles Dickens, “Barnaby Rudge. Chapter 40.”, in Master Humphrey’s Clock, volume III, London: Chapman & Hall, […], →OCLC

   "Now, father," said Nancy, "is there any call for you to go home to tea? Mayn't you just as well stay with us?--such a beautiful evening as it's likely to be."

   1861, George Eliot [pseudonym; Mary Ann Evans], chapter XVII, in Silas Marner: The Weaver of Raveloe, Edinburgh; London: William Blackwood and Sons, →OCLC

   You mayn't hardly believe it, but at the present moment I am absolutely without a farthing.

   1914, Saki, The Romancers

   I can't help about other people. But I surely would like to have a spot to stop till daylight. Still - if people don't relish this place, mayn't it be because it's getting so run-down?

   1930, H. P. Lovecraft, Madusa's Coil