dyke (note on the origin of the word)
1931, Amer.Eng., probably shortening of morphadike, dialectal garbling of hermaphrodite, but bulldyker "engage in lesbian activities" is attested from 1921, and a source from 1896 lists dyke as slang for "the vulva."
(from Online Etymology Dictionary, © 2010 Douglas Harper)
"Who's the dyke in the cowboy boots?" (Rude and derogatory.) (Source: Dictionary of American Slang and Colloquial Expressions by Richard A. Spears.Fourth Edition. © 2007. Published by McGraw Hill).