Meaning

noun a heavy silvery toxic univalent and bivalent metallic element; the only metal that is liquid at ordinary temperatures

adjective liable to sudden unpredictable change

originFrom Middle English quyk silver, quyksilver, quikselver, from Old English cwicseolfor (“quicksilver”, literally “living silver”) (see Latin argentum vīvum) from its ability to move. See quick in the sense of "living". Cognate with Dutch kwikzilver, German Low German Quicksülver, German Quecksilber, Danish kviksølv, Norwegian Bokmål kvikksølv, Swedish kvicksilver. By surface analysis, quick…

Etymology from Wiktionary, CC BY-SA 3.0