Fluctuant is an adjective that describes something that is unpredictable and unstable. It can be used to describe a variety of things, from the stock market to relationships. The crossword solutions for this term are ERRATIC (7 letters), INCALCULABLE (12 letters), INSECURE (8 letters), CHANCY (6 letters), and IFFY (4 letters). All of these words are synonyms for fluctuant, and they all describe something that is uncertain and unreliable.