flightiness

Flightiness is the tendency to change your mind or be unpredictable. Your best friend's flightiness means it's hard to make definite plans with her — you can't count on her to show up on time.

Flightiness is generally thought of as a negative quality, since it means you can't count on someone to be dependable or responsible. Your flightiness shows in the way you flit from one interest to another or change your mind about which movie to see or who you're going to the prom with. The adjective flighty meant "swift" in the 1500's, but two centuries later it came to describe a skittish horse, and finally a "fickle or frivolous" person.

Definitions of flightiness

1. noun

   the trait of acting unpredictably and more from whim or caprice than from reason or judgment
   “I despair at the flightiness and whimsicality of my memory”

   synonyms: arbitrariness, capriciousness, whimsey, whimsicality, whimsy

   type of:

   irresponsibility, irresponsibleness

   a form of untrustworthiness; the trait of lacking a sense of responsibility and not feeling accountable for your actions