1560s, "well able to manage for oneself, fertile in expedients," from shift (n.1) in secondary sense of "dodge, trick, artifice" + -y (2). The meaning "habitually using dishonest methods, characterized by trickery, not straightforward" is by 1837. Of the wind, in a sense of "prone to shifting," by 1884. Related: Shiftily; shiftiness.
updated on September 07, 2022