1a. In a somersault; upside down; head first. * /It was so dark Bob fell head over heels into a big hole in the ground./ Compare: UPSIDE DOWN. 1b. In great confusion or disorder; hastily. * /The children all tried to come in the door at once, head over heels./ Compare: TOPSY-TURVY. 2. {informal} Completely; deeply. * /He was head over heels in debt./ * /She was head over heels in love./
See: HEAD OVER HEELS.