"study," from O.E. cunnan "to know, know how" (see can
"swindle," 1889, Amer.Eng., from confidence man (1849), from the many scams in which the victim is induced to hand over money as a token of confidence. Confidence with a sense of "assurance based on insufficient grounds" dates from 1590s. Con also can be a slang or colloquial shortening of several other
con- words in English, e.g., from the 19th century, confidant, conundrum, conformist, contract, and from the 20th century, convict, conductor.
"to guide ships," 1626, from Fr. conduire, from L. conducere (see conduce