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The literal sense is obsolete in English; the sense of "elegant, cultured" (of literature, arts, etc.)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]