mid-15c., "philosopher, sage," from Middle English wys "wise" (see wise (adj.)) + -ard. Cf. 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" 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.
a pretender to supernatural knowledge and power, "a knowing one," as the original Hebrew word signifies. Such an one was forbidden on pain of death to practise his deceptions (Lev. 19:31; 20:6, 27; 1 Sam. 28:3; Isa. 8:19; 19:3).