head over heels (in love), to be/fall

head over heels

Completely enamored of someone, typically a new romantic partner. This phrase is sometimes followed by "in love." Oh, I know he's head over heels in love with Christina—he won't stop gushing about her! We used to be head over heels, but now we just annoy each other most of the time.
See also: head, heel, over

head over heels

Completely, thoroughly, as in They fell head over heels in love. This expression originated in the 1300s as heels over head and meant literally being upside down. It took its present form in the 1700s and its present meaning in the 1800s.
See also: head, heel, over

head over heels

upside down; turning over completely in a forward motion, as in a somersault.
The earlier, more logical, version of this phrase was heels over head ; the normal modern form dates from the late 18th century. It is often used figuratively of an extreme condition, as in head over heels in love , ‘madly in love’, or head over heels in debt , ‘deeply in debt’.
See also: head, heel, over

head over ˈheels (in ˈlove)

completely in love: He’s head over heels in love with his new girlfriend.
See also: head, heel, over

head over heels (in love), to be/fall

So completely that one is upside down. This expression began life as heels over head, a far more logical description of being turned upside down, and appeared in print in a collection of Early English Alliterative Poems dating from ca. 1350. Four hundred years later an unknown poet turned the saying around: “He gave [him] such an involuntary kick in the face as drove him head over heels” (The Contemplative Man, 1771). This corruption stuck, but the principal sense in which the term is now used dates only from the nineteenth century. An early appearance in print is in David Crockett’s Narrative of the Life of David Crockett (1834): “I soon found myself head over heels in love with this girl.”
See also: fall, head, heel, over