saleswoman n.

"of or pertaining to sale, sales, or the business of selling," word-forming element from genitive of sale (n.), by 1520s, in salesman. Cf. saleswork "work done for sale" (1775). For earlier use of similar formations, compare craftsman, oarsman, both Middle English. Sales tax is attested by 1886; sales clerk by 1863; sales associate by 1946. Sales representative is from 1910.

"adult female human," late Old English wimman, wiman (plural wimmen), literally "woman-man," alteration of wifman (plural wifmen) "woman, female servant" (8c.), a compound of wif "woman" (see wife) + man "human being" (in Old English used in reference to both sexes; see man (n.)). Compare Dutch vrouwmens "wife," literally "woman-man."

It is notable that it was thought necessary to join wif, a neuter noun, representing a female person, to man, a masc. noun representing either a male or female person, to form a word denoting a female person exclusively. [Century Dictionary]

The formation is peculiar to English and Dutch. Replaced older Old English wif and quean as the word for "female human being," as in Jesus's answer to his mother, in Anglo-Saxon gospels la, wif, hwæt is me and þe? (John ii:4 "Woman, what have I to do with thee?").

The pronunciation of the singular altered in Middle English by the rounding influence of -w-; the plural retains the original vowel. Meaning "wife," now largely restricted to U.S. dialectal use, is attested from mid-15c.

In American English, lady is "In loose and especially polite usage, a woman" [Craigie, "Dictionary of American English"]. This peculiarity was much commented upon by English travelers; in the U.S. the custom was considered especially Southern, but the English didn't bother with nice distinctions and regarded it simply as American. "This noble word [woman], spirit-stirring as it passes over English ears, is in America banished, and 'ladies' and 'females' substituted; the one to English taste mawkish and vulgar; the other indistinctive and gross. The effect is odd." [Harriet Martineau, 1837]

Woman-hater "misogynist" is from c. 1600. Women's work, that considered appropriate to women, is from 1660s. Women's liberation is attested from 1966; women's rights is from 1840, with an isolated example in 1630s.