quicksilver

noun

1. (uncountable)The metal mercury.
2. (broadly, uncountable)An amalgam of mercury and tin applied to the backs of mirrors; quicksilvering.

adj

1. (not-comparable)Unpredictable, erratic, or fickle; mercurial.

   “Summer is not the most auspicious season for theater in New York. Aside from a few certifiable Broadway hits, it is, in fact, a rather quicksilver commodity.”

   “The idea of a merchant selling both totems of pure evil and frozen yogurt (he calls it frogurt!) is amusing in itself, as is the idea that frogurt could be cursed, but it’s really the Shopkeeper’s quicksilver shift from ominous doomsaying to chipper salesmanship that sells the sequence.”

verb

1. (transitive)To overlay with quicksilver.
2. (transitive)To treat with quicksilver.