Synonyms: whimsey, whimsicality, whimsy, arbitrariness, capriciousness, flightiness
Definition: the trait of acting unpredictably and more from whim or caprice than from reason or judgment
Usage: I despair at the flightiness and whimsicality of my memory
Similar words: irresponsibility, irresponsibleness
Definition: a form of untrustworthiness; the trait of lacking a sense of responsibility and not feeling accountable for your actions