The word and meaning are from ©2018 Merriam-Webester, Incorporated.
Mercurial – “having the qualities of eloquence, ingenuity, or thievishness attributed to the god Mercury or to the influence of the planet Mercury”. “Unpredictably changeable.”
I had never heard of the word, nor did I know it was related to Mercury – a Roman god. At the same time I was able to acquire another word “thievishness”. I learned that Mercury was over the merchants and thieves.
Today is a great day to learn a new word each day and then use them before you forget them. It will make a difference when the communications are better.