"Low German dialect of northern Germany," 1814, from German, from Dutch platduits, literally "flat (or low) German," from plat "flat, plain, clear" + duits "German" (see Dutch). In contrast to the speech of the upland parts of Germany (High German).
1749, "pertaining to or characterized by sentiment, appealing to sentiment rather than reason," from sentiment + -al (1). At first without pejorative connotations; the meaning "too tender-hearted, apt to be swayed by sentiment" is attested by 1768 (implied in sentimentality). The French word is said to be from English. Related: Sentimentally.
"equivocate, evade the point, trifle in an argument or discourse, turn from the point in question or the plain truth," 1650s, from quibble (n.). Earlier "to pun" (1620s). Related: Quibbled; quibbler; quibbling.
Sense evolution probably is from "smooth" (c. 1300), to "slim, slender; of light texture," hence "not good or strong; insubstantial, trifling, inferior, insignificant" (early 14c.). Meaning "small in amount" is from 1520s. Sense of German cognate schlecht developed from "smooth, plain, simple" to "bad, mean, base," and as it did it was replaced in the original senses by schlicht, a back-formation from schlichten "to smooth, to plane," a derivative of schlecht in the old sense [Klein].
c. 1200, cruelte, "indifference to, or pleasure taken in, the distress or suffering of any sentient being," from Old French crualté (12c., Modern French cruauté), from Latin crudelitatem (nominative crudelitas) "cruelty," from crudelis "rude, unfeeling; cruel, hard-hearted," related to crudus "rough, raw, bloody" (see crude). Meaning "a cruel act" is from late 14c.
"serving to explain, containing explanation," 1610s, from or modeled on Late Latin explanatorius "having to do with an explanation," from Latin explanat-, past-participle stem of explanare "make plain or clear" (see explanation).
mid-15c., rustik, "associated with the country, rural," from Latin rusticus "of the country, rural; country-like, plain, simple, rough, coarse, awkward," from rus (genitive ruris) "open land, country" (see rural).
From 1580s, of persons, "having the look and manner of country folk, wanting refinement." By 1590s of rude or undressed workmanship. By c. 1600 as "plain and simple, having the charm of the country."
The noun meaning "a country person, peasant" is from 1550s (also in classical Latin). Related: Rustical "living in the country," early 15c., rusticalle, from Medieval Latin rusticalis.
1580s as a noun; 1732 as an adjective, in reference to Chaldea, the rich plain of southern Babylon, or the people who lived there, with + -an + Latin Chaldaeus, from Greek Khaldaios, from Aramaic (Semitic) Kaldaie, from Akkadian (mat)Kaldu "the Chaldeans."