Synonyms and related words :
adrift, afloat, alternating, amorphous, capricious, changeable, changeful, coquettish, desultory, deviable, dizzy, eccentric, erratic, faddish, fast and loose, fickle, fitful, flickering, flighty, flirtatious, flitting, fluctuant, fluctuating, fluctuational, freakish, giddy, harmonic, impetuous, impulsive, inconsistent, inconstant, indecisive, infirm, irregular, irresolute, irresponsible, libratory, light, mazy, mercurial, moody, nutational, oscillating, oscillatory, pendular, pendulating, pendulous, periodic, quicksilver, rambling, resonant, restless, roving, scatterbrained, shapeless, shifting, shifty, shilly-shally, shilly-shallying, shuffling, skittish, spasmodic, spineless, toying, unaccountable, uncertain, uncontrolled, undependable, undisciplined, unfixed, unpredictable, unreliable, unrestrained, unsettled, unstable, unstable as water, unstaid, unsteadfast, unsteady, vacillatory, vagrant, variable, versatile, vibratile, vibrating, vibratory, vicissitudinary, vicissitudinous, volatile, wandering, wanton, wavering, wavery, wavy, wayward, whimsical, wishy-washy, wobbly