early 15c., "philosopher, sage," from Middle English wys "wise" (see wise, adj.) + -ard. Compare Lithuanian zynyste "magic," zynys "sorcerer," zyne "witch," all from zinoti "to know." The ground sense is perhaps "to know the future." The meaning "one with magical power, one proficient in the occult sciences" did not emerge distinctly until c.1550, the distinction between philosophy and magic being blurred in the Middle Ages. As a slang word meaning "excellent" it is recorded from 1922.