Open English Wordnet
Nouns
(n)mercury, quicksilver, hydrargyrum, Hg, atomic number 80a heavy silvery toxic univalent and bivalent metallic element; the only metal that is liquid at ordinary temperatures
Adjectives
(s)erratic, fickle, mercurial, quicksilverliable to sudden unpredictable change“erratic behavior”, “fickle weather”, “mercurial twists of temperament”, “a quicksilver character, cool and willful at one moment, utterly fragile the next”