inconstant
in.con.stant \-st*nt\ aj [ME, fr. MF, fr. L inconstant-, inconstans, fr. in- + cons]tant-, constans constant : likely to change frequently without apparent or cogent reason INCONSTANT implies an incapacity for steadiness and an inherent tendency to change; FICKLE suggests unreliability because of perverse changeability and incapacity for steadfastness; CAPRICIOUS suggests motivation by sudden whim or fancy and stresses unpredictability; MERCURIAL implies a rapid changeability in mood esp. from depression to elation; UNSTABLE implies an incapacity for remaining in a fixed position or steady course and applies esp. to a lack of emotional balance - in.con.stant.ly av SYN syn FICKLE, CAPRICIOUS, MERCURIAL, UNSTABLE:
Webster's English Dictionary