Head over heels Informal

Madly, overwhelmingly in love with someone, often suddenly or intensely.

It’s used with warmth and a touch of exaggeration — the feeling is total and slightly dizzying, as the physical image behind the phrase suggests.

The phrase was originally “heels over head,” describing a literal tumble or cartwheel, and appears in this form as early as 1648 in “The Devill Seen at St. Albons” and again in a 1653 English translation of Rabelais’s “Gargantua et Pantagruel.” The order flipped to the now-familiar “head over heels” by the late 17th century — appearing in a 1687 translation of “Don Quixote” describing a tumble through water, and in the 1694 “The French Rogue,” describing someone tumbling “Head over Heels” down stairs — though the exact reason for the reversal is not documented. The romantic sense, oddly, has no clear connecting event either: the earliest known instance of “head over heels” describing lovesickness rather than a physical tumble is a 1711 English translation of the ancient Greek satirist Lucian, describing a lovestruck figure “reeling and tumbling Head over Heels” — suggesting the two meanings (falling physically, and “falling” for someone) simply reinforced each other through the shared image of someone thrown off balance.

She’s head over heels for her new boyfriend.

He fell head over heels the moment they met.

They’re head over heels in love after just a month.

A: “How’s the new relationship going?” B: “I’m head over heels, honestly.”