Megrim(noun)
(A sudden desire or change of mind, especially one that is unusual or unexplained.)
Hindi meaning:सनक/झक
Synonyms: Whim, Impulse, Urge, Caprice, Craze, Fad
Antonyms: Certainty
Example: Having no sense of purpose, the wayward was often at the mercy of the strange megrims that sprang into his head.
Trick to remember: Mandarin language sikhne ka Megrim hai. 
