sexist (adj.)

late 14c., "males or females collectively," from Latin sexus "a sex, state of being either male or female, gender," of uncertain origin. "Commonly taken with seco as division or 'half' of the race" [Tucker], which would connect it to secare "to divide or cut" (see section (n.)).

Secus seems the more original formation, but it is strange that the older texts only know sexus. The modern meaning of sectiō 'division' suggests that sec/xus might derive from secāre 'to sever', but the morphology remains unclear: does sexus go back to an s-present *sek-s- 'to cut up', or was it derived from a form *sek-s- of the putative s-stem underlying secus?  [Michiel de Vaan, "Etymological Dictionary of Latin and the other Italic Languages," Leiden, 2008]

Meaning "quality of being male or female" first recorded 1520s. Meaning "sexual intercourse" is attested by 1906; the meaning "genitalia" is attested by 1938. Sex appeal is attested by 1904.

For the raw sex appeal of the burlesque "shows" there is no defense, either. These "shows" should be under official supervision, at the least, and boys beneath the age of eighteen forbidden, perhaps, to attend their performance, just as we forbid the sale of liquors to minors. [Walter Prichard Eaton, "At the New Theatre and Others: The American Stage, Its Problems and Performances," Boston, 1910]

Sex drive is by 1918; sex object by 1901; sex symbol by 1871 in anthropology; the first person to whom the term was applied seems to have been Marilyn Monroe (1959). Sex therapist is from 1974.

1932 (as an adjective from 1938), from race (n.2) + -ist. Racism (q.v.) is in use by 1928, originally in the context of fascist theories, and common from 1936. These words replaced earlier racialism (1882) and racialist (1910), both often used early 20c. in a British or South African context. There are isolated uses of racism from c. 1900.

Returning recently from a six months' visit to Europe, the Rev. John LaFarge, noted Catholic writer, warned at a dinner given in his honor that the destructive forces of "racism" are increasing in the United States, and that they could cause irreparable harm among the American people if immediate steps are not taken to combat them.

Father LaFarge said that American racism is directed principally against Negroes, Jews, and foreigners. He described it as "the pale but venomous cousin" of Nazi racism. Like its Nazi counterpart, he added, it has erected impassable barriers between extensive regions and large groups of people, has formed its own myths and moulded its own social institutions, and above all has come consistently into conflict with Christian teachings. [Opportunity, Journal of Negro Life, vol. XVII, No. 2, Feb. 1939]

Earlier, race hatred (1852 of the Balkans, 1858 of British India, 1861 of white and black in America), race prejudice (1867 of English in India, 1869 of white and black in America, 1870 of the English toward Irish) were used, and, especially in 19c. U.S. political contexts, negrophobia. Anglo-Saxonism as "belief in the superiority of the English race" had been used (disparagingly) from 1860. Anti-Negro (adj.) is attested in British and American English from 1819.