inconstant

synonyms inconstant , fickle , capricious , mercurial , unstable mean lacking firmness or steadiness (as in purpose or devotion). inconstant implies an incapacity for steadiness and an inherent tendency to change <an inconstant friend>. fickle suggests unreliability because of perverse changeability and incapacity for steadfastness <performers discover how fickle fans can be>. capricious suggests motivation by sudden whim or fancy and stresses unpredictability <an utterly capricious critic>. mercurial implies a rapid changeability in mood <made anxious by her boss's mercurial temperament>. unstable implies an incapacity for remaining in a fixed position or steady course and applies especially to a lack of emotional balance <too unstable to hold a job>.