"insincere talk," 1709, earlier, slang for "whining of beggars," (1560s), from O.N.Fr. canter "to sing, chant" from L. cantare, freq. of canere "to sing" (see chant). Sense in English developed after 1680 to mean the jargon of criminals and vagabonds, then applied contemptuously by any sect or school to the phraseology of its rival.
"slant," late 14c., Scottish, from O.N.Fr. cant (perhaps via M.L.G. kante or M.Du. kant), from V.L. *canthus, from L. cantus "iron tire of a wheel," possibly from a Celt. word meaning "rim of wheel, edge," from PIE base *kantho- "corner, bend" (cf. Gk. kanthos "corner of the eye").