hot-foot adv.

Old English hat "hot, flaming, opposite of cold," used of the sun or air, of fire, of objects made hot; also "fervent, fierce, intense, excited," from Proto-Germanic *haita- (source also of Old Saxon and Old Frisian het, Old Norse heitr, Middle Dutch and Dutch heet, German heiß "hot," Gothic heito "heat of a fever"), of uncertain origin, perhaps related to Lithuanian kaisti "to grow hot;" both could be from a substratum word.

With a long vowel in Middle English (rhyming with boat, wrote) which shortened in modern English, perhaps from influence of comparative hotter. As an adverb, Old English hote.

Hot as "full of sexual desire, lustful" is from c. 1500; the sense of "inciting desire" is 18c. Taste sense of "pungent, acrid, biting" is from 1540s. Sense of "exciting, remarkable, very good" is 1895; that of "stolen" is first recorded 1925 (originally with overtones of "easily identified and difficult to dispose of"); that of "radioactive" is from 1942. Of jazz music or combos from 1924.

Hot flashes in the menopausal sense attested from 1887. Hot stuff for anything good or excellent is by 1889, American English. Hot seat is from 1933. Hot potato in figurative sense is from 1846 (from being baked in the fire coals and pulled out hot). Hot cake is from 1680s; to sell like hot cakes is from 1839.

The hot and cold in hide-and-seek or guessing games (19c.) are from hunting (1640s), with notion of tracking a scent. Hot and bothered is by 1921. Hot under the collar in the figurative sense is from 1895.

"terminal part of the leg of a vertebrate animal," Old English fot "foot," from Proto-Germanic *fōts (source also of Old Frisian fot, Old Saxon fot, Old Norse fotr, Danish fod, Swedish fot, Dutch voet, Old High German fuoz, German Fuß, Gothic fotus "foot"), from PIE root *ped- "foot." Plural form feet is an instance of i-mutation.

The linear measure was in Old English (the exact length has varied over time), this being considered the length of a man's foot; a unit of measure used widely and anciently. In this sense the plural is often foot. The current inch and foot are implied from measurements in 12c. English churches (Flinders Petrie, "Inductive Metrology"), but the most usual length of a "foot" in medieval England was the foot of 13.2 inches common throughout the ancient Mediterranean. The Anglo-Saxon foot apparently was between the two. All three correspond to units used by the Romans, and possibly all three lengths were picked up by the Anglo-Saxons from the Romano-Britons. "That the Saxon units should descend to mediæval times is most probable, as the Normans were a ruling, and not a working, class." [Flinders Petrie, 1877]. The medieval Paul's Foot (late 14c.) was a measuring standard cut into the base of a column at the old St. Paul's cathedral in London. The metrical foot (late Old English, translating Latin pes, Greek pous in the same sense) is commonly taken to represent one rise and one fall of a foot: keeping time according to some, dancing according to others.

In Middle English also "a person" (c. 1200), hence non-foot "nobody." Meaning "bottom or lowest part of anything eminent or upright" is from c. 1200. Of a bed, grave, etc., from c. 1300. On foot "by walking" is from c. 1300. To get off on the wrong foot is from 1905 (the right foot is by 1907); to put one's best foot foremost first recorded 1849 (Shakespeare has the better foot before, 1596); Middle English had evil-foot (adv.) "through mischance, unluckily." To put one's foot in (one's) mouth "say something stupid" is attested by 1942; the expression put (one's) foot in something "make a mess of it" is from 1823. To have one foot in the grave "be near death" is from 1844. Colloquial exclamation my foot! expressing "contemptuous contradiction" [OED] is attested by 1923, probably euphemistic for my ass in the same sense, which dates to 1796 (also see eyewash).