1610s, "of or belonging to the highest class; approved as a model," from French classique (17c.), from Latin classicus "relating to the (highest) classes of the Roman people," hence, "superior," from classis (see class (n.)). Originally in English, "of the first class;" meaning "belonging to or characteristic of standard authors of Greek and Roman antiquity" is attested from 1620s.
1772, "action of classifying, act of forming a class or dividing into classes," noun of action from Latin stem of classify, or from French classification. Meaning "result of classifying" is from 1789.
"having lost one's place in the social order," 1887, from French déclassé, past participle of déclasser "to cause to lose class," from de-, privative prefix (see de-) + classer "to class," from classe (n.), from Latin classis (see class (n.)). In italics in English until c. 1920; nativized form declassed is attested from 1873.
Fallen or put out of one's proper class or place or any definite and recognized position or rank in the social system: applied to persons who by misfortune or their own fault have lost social or business standing, and are not counted as part of any recognize class of society. [Century Dictionary, 1897]