15c. metathesis of Middle English drit, drytt "excrement, dung, feces, any foul or filthy substance," also "mud, earth," especially "loose earth" (c. 1300), from Old Norse drit, cognate with Old English dritan "to void excrement," from Proto-Germanic *dritan (source also of Dutch drijten, Old High German trizan).
Used abusively of persons from c. 1300; figurative of something worthless from early 14c. Meaning "gossip" first attested 1926 (in Hemingway).
As an adjective, "consisting or made of loose earth," by 1860. The dirt-bike is attested by 1970. Dirt-cheap "as cheap as dirt" is by 1766; dirt-poor "extremely poor" is by 1906. Dirt road, one not paved or macadamized, is attested by 1835, American English. Pay-dirt "earth containing gold" is by 1857, originally California miners' slang.
It is customary to speak of "the golden sands of California;" but a person who should believe that the gold is found in pure sand, would be far wrong. Usually, the pay-dirt is a very stiff clay, full of large gravel and stones. The depth of this pay-dirt varies. In a gully where the water is not more than five feet wide in the heaviest rain, the pay dirt will not usually be more than a foot deep. (etc.) [John S. Hittell, "Mining in the Pacific States of North America," San Francisco, 1861]
"of or imparting filth," early 15c. metathesis of dritty "feculent; muddy" (late 14c.), from dirt + -y (2). Sense of characterized by dirt, unclean" is from 16c. Meaning "smutty, morally unclean" is from 1590s. Of colors, from 1690s. Sense of "not streamlined; rough, untidy, or imperfect" is by 1925. Of atomic bombs, "producing much radioactive fallout," by 1956.
Dirty linen "personal or familial secrets" is first recorded 1860s. Dirty work in the figurative sense is from 1764; dirty trick is from 1670s. Dirty joke is by 1856. The dirty look someone gives you is by 1923; dirty old man "superannuated lecher" is from 1932. Related: dirtiness.
1590s, from French squalide and directly from Latin squalidus "rough, coated with dirt, filthy," related to squales "filth," squalus "filthy," squalare "be covered with a rough, stiff layer, be coated with dirt, be filthy," of uncertain origin. Related: Squalidly; squalidness; squalidity.
"muddy, covered with clay," from Latin lutosus, from lutum "mud, dirt, mire, clay," from Proto-Italic *luto-, *lustro-, from PIE *l(h)u-to- "dirt," *l(h)u-(s)tro- "dirty place," from root *leu- "dirt; make dirty" (cognates: Greek lythron "gore, clotted blood," lyma "dirty water; moral filth, disgrace," lymax "rubbish, refuse," lyme "maltreatment, damage;" Latin lues "filth;" Old Irish loth "mud, dirt;" Welsh lludedic "muddy, slimy; Albanian lum "slime, mud;" Lithuanian liūtynas "loam pit").
Hence also English lute (n.) as a type of tenacious clay or cement used to stop holes, seal joints, etc. (c. 1400), from Old French lut or Medieval Latin lutum, from the Latin noun. Lute also was a verb in English.