N changeableness, mutability, inconstancy, versatility, mobility, instability, unstable equilibrium, vacillation, fluctuation, vicissitude, alternation, restlessness, fidgets, disquiet, disquietude, inquietude, unrest, agitation, moon, Proteus, chameleon, quicksilver, shifting sands, weathercock, harlequin, Cynthia of the minute, April showers, wheel of Fortune, transientness, changeable, changeful, changing, mutable, variable, checkered, ever changing, protean, proteiform, versatile, unstaid, inconstant, unsteady, unstable, unfixed, unsettled, fluctuating, restless, agitated, erratic, fickle, irresolute, capricious, touch and go, inconsonant, fitful, spasmodic, vibratory, vagrant, wayward, desultory, afloat, alternating, alterable, plastic, mobile, transient, wavering, seesaw, off and on, a rolling stone gathers no moss, pictra mossa non fa muschis, honores mutant mores, varium et mutabile semper femina.

For further exploring for "alternating" in Webster Dictionary Online