īn-stabilis e, adj., not steadfast, unsteady, unstable, tottering, not firm: ingressus, L.: cymbae, V.: naves, Cu.: acies, shaken, L.

—Giving no support: tellus, O.

—Fig., unstable, inconstant, changeable, fickle: instabilem motum habere, Cs.: coniugium, Iu.: animus, V.