adj. gid·di·er, gid·di·est
a. Having a reeling, lightheaded sensation; dizzy.
b. Causing or capable of causing dizziness: a giddy climb to the topmast.
2. Frivolous and lighthearted; flighty: was giddy with excitement at the news.
intr. & tr.v. gid·died, gid·dy·ing, gid·dies
To become or make giddy.
[Middle English gidi, crazy, from Old English gidig; see gheu(ə)- in the Appendix of Indo-European roots.]
Word History: Though little trace of a divine provenance can be discerned in its modern meaning, giddy is derived from the same ancient Germanic word (*gudam) that has given us the word God. The Germanic word *gudigaz, formed from the word *gudam, meant "possessed by a god." Such possession can be a rather unbalancing experience, and so it is not surprising that the Old English descendant of *gudigaz, gidig, meant "mad, possessed by an evil spirit," or that the Middle English development of gidig, gidi, meant the same thing, as well as "foolish," "mad (used of an animal)," "dizzy," and "uncertain, unstable." Our sense "lighthearted, frivolous" represents the ultimate secularization of giddy.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.