Pronounced: SIR-burr-us, noun
Notes: Another word for which I know the etymology, but didn’t know the meaning
Yesterday’s word
The word vagary is “an erratic, unpredictable, or extravagant manifestation, action, or notion”
First usage
Our word came into English in the mid-1500s
Background / Comments
I am used to coming across our word in the plural, and, from the context, thought it meant “unpredictability”, which turns out to be the commonly-used form and meaning of our word. When our word first showed up, to “make a vagary” meant that you took a wandering journey, or – in a figurative sense – you wandered from the correct path by committing some offense (usually minor). If one spoke or wrote vagaries, one was wandering from the main subject. It is thought that our word came from the Latin word vagari (to wander).
Richard's Vocabulary Word-of-the-Day 