Vagary

n.	1.
	1.	A wandering or strolling.
	2.	Hence, a wandering of the thoughts; a wild or fanciful freak; a whim; a whimsical purpose. They changed their minds, Flew off, and into strange vagaries fell. - Milton.

Noun

1.

vagary - an unexpected and inexplicable change in something (in a situation or a person's behavior, etc.); "the vagaries of the weather"; "his wealth fluctuates with the vagaries of the stock market"; "he has dealt with human vagaries for many years"

aberration, bee, boutade, brainstorm, capriccio, circuitousness, crank, craze, crazy idea, crosswiseness, crotchet, declination, deflection, deflexure, deviance, deviation, deviousness, diagonality, digression, divagation, divergence, dream, excursion, fad, fantastic notion, flimflam, fool notion, freak, freakish inspiration, harebrained idea, humor, indirection, indirectness, kink, maggot, megrim, nonconformity, obliqueness, obliquity, passing fancy, skewness, squint, toy, transverseness, whim-wham