Capricious

adjective/kəˈpɹɪʃəs/character

Definition

Given to sudden and unaccountable changes of mood or behavior.

Etymology

Borrowed from Middle French capricieux, from Italian capriccioso, from capriccio. By surface analysis, caprice +‎ -ious.

Synonyms

arbitrary, whimsical, fickle, flighty, wayward

In a sentence