"having a sharp taste," late 14c., perhaps from Old English teart "painful, sharp, severe" (in reference to punishment, pain, suffering), of unknown origin; possibly related to the root of teran "to tear." Figurative use, with reference to words, speech, etc., is attested from c.1600.
"small pie," c.1400, from Old French tarte "flat, open-topped pastry" (13c.), possibly an alteration of torte, from Late Latin torta "round loaf of bread" (in Medieval Latin "a cake, tart"), infl. in Middle English by tart (adj.).
A promiscuous woman, esp a prostitute; harlot; hooker: nothing cheap for us like the grimy tarts on Mercury Street
[1887+; fr tart, the pastry confection, esp the English jam-tart; in original early 1800s use it meant any pleasant or attractive woman and only specialized at the end of the century]