late 14c., "polished, burnished" (mid-13c. as a surname), from Latin politus "refined, elegant, accomplished," literally "polished," past participle of polire "to polish, to make smooth" (see polish (v.)).
The literal sense is obsolete in English; the sense of "elegant, cultured" (of literature, arts, etc.) is from c. 1500; of persons, "refined or cultivated in speech, manner, or behavior," by 1620s. The meaning "behaving courteously, showing consideration for others" is by 1748 (implied in politely). Related: Politeness.
Polite applies to one who shows a polished civility, who has a higher training in ease and gracefulness of manners: politeness is a deeper, more comprehensive, more delicate, and perhaps more genuine thing than civility. Polite, though much abused, is becoming the standard word for the bearing of a refined and kind person toward others. [Century Dictionary, 1895]
"civility, politeness," 1717, from French politesse (17c.), from Italian politezza, properly "the quality of being polite," from polito "polite," from Latin politus (see polite). "In mod. usage generally with depreciatory connotation" [OED].
early 14c., polishen "make smooth or glossy" by friction or coating (of the surface of wood, stone, metal, etc.), from Old French poliss-, present participle stem of polir (12c.) "to polish, decorate, see to one's appearance," from Latin polire "to polish, make smooth; decorate, embellish;" figuratively "refine, improve," said by Watkins to be from PIE root *pel- (5) "to thrust, strike, drive," via the notion of fulling cloth, but there are other guesses.
The figurative sense of "free from coarseness, to refine" in English is recorded from mid-14c. Compare polite. Related: Polished; polishing. To polish off "finish" is by 1829 in pugilism slang, probably from the application of a coat of polish as the final step in a piece of work.