Dizzy sounds like it should be a fairly recent coinage. The double z makes it seem very modern and the word has a slangy air about it. But this couldn’t be further from the truth. Dizzy is a very old word, going back to the Old English dysig or dyseg, meaning foolish or stupid. The word appears in the Vespasian Psalter from c.825:
swe folc dysig
(such dizzy folk)
And in the Lindisfarne Gospel of Matthew, c.950:
gelic bið were dysge se ðe getimberde hus his ofer sonde
(is like a dizzy man who built his house upon sand)1
This sense seems to have dropped out of general use in the 13th century, being preserved in the dialectal speech of northern England until the late 19th century, when it reemerged in America and reentered general use. From the 1878 Funny Fatherland: A Leg-end of the Rhine:
She has seen many a dizzy Blond in America, and don’t think they are so wonderful.2
The sense meaning giddy, subject to a whirling sensation, or prone to vertigo appears in the 14th century. From Richard Rolle of Hampole’s c.1340 The Pricke of Conscience:
Than waxes his hert hard and hevy. And his heved feble and dysy.3
2Historical Dictionary of American Slang, v. 1, A-G, edited by Jonathan Lighter (New York: Random House, 1994), 610.
3OED2, dizzy, a.
Copyright 1997-2017, by David Wilton