get in someone's hair, Slang. to annoy or bother someone: Their snobbishness gets in my hair.
hair of the dog, Informal. a drink of liquor, supposed to relieve a hangover: Even a hair of the dog didn't help his aching head.Also hair of the dog that bit one.
let one's hair down, Informal.
to relax; behave informally: He finally let his hair down and actually cracked a joke.
to speak candidly or frankly; remove or reduce restraints: He let his hair down and told them about his anxieties.
make one's hair stand on end, to strike or fill with horror; terrify: The tales of the jungle made our hair stand on end.
split hairs, to make unnecessarily fine or petty distinctions: To argue about whether they arrived at two o'clock or at 2:01 is just splitting hairs.
tear one's hair, to manifest extreme anxiety, grief, or anger: He's tearing his hair over the way he was treated by them.Also tear one's hair out.
to a hair, perfect to the smallest detail; exactly: The reproduction matched the original to a hair.
without turning a hair, without showing the least excitement or emotion.Also not turn a hair.
Origin of hair
before 900;Middle Englishheer,Old Englishhǣr (cognate with Dutch,Germanhaar,Old Norsehār), with vowel perhaps from Middle Englishhaire hair shirt < Old French < Old High Germanhāria (cognate with Middle Englishhere,Old Englishhǣre,Old Norsehǣra)
Related formshair·like, adjectivede·hair, verb (used with object)Can be confusedhairhare
Old English hær "hair, a hair," from Proto-Germanic *khæran (cf. Old Saxon, Old Norse, Old High German har, Old Frisian her, Dutch and German haar "hair"), perhaps from PIE *ghers- "to stand out, to bristle, rise to a point" (cf. Lithuanian serys "bristle;" see horror).
Spelling influenced by Old Norse har and Old English haire "haircloth," from Old French haire, from Frankish *harja or some other Germanic source (see above). To let one's hair down "become familiar" is first recorded 1850. Phrase hair of the dog that bit you (1540s), homeopathic remedy, is in Pliny.
One of the fine strands that grow from the skin of mammals, usually providing insulation against the cold. Modified hairs sometimes serve as protective defenses, as in the quills of a porcupine or hedgehog, or as tactile organs, as in the whiskers (called vibrissae) of many nocturnal mammals. Hair filaments are a modification of the epidermis of the skin and are composed primarily of keratin. Hair also contains melanin, which determines hair color.
A slender growth resembling a mammalian hair, found on insects and other animals.
A fine, threadlike growth from the epidermis of plants. See more at trichome.
Also, let down one's hair. Drop one's reserve or inhibitions, behave casually or informally, as in Whenever the two sisters get together, they let their hair down and discuss all their problems. This expression alludes to the practice of women taking down their pinned-up long hair only in the privacy of the bedroom. [c. 1900]