1706, traditionally named for a British physician during reign of Charles II (a story traceable to 1709), but there is no evidence for that. Also spelled condam, quondam, which suggests it may be from Italian guantone, from guanto "a glove." A word omitted in the original OED (c.1890) and not used openly in the U.S. and not advertised in mass media until November 1986 speech by Surgeon General C. Everett Koop on AIDS prevention. Compare prophylactic.