Definition of unstable:
perilous, timid, continue, wonky, hazardous, coseismic, firm, unassured, tottering, mobile, bad, smooth, reactive, disturbed, sensitive, rocky, rickety, dubious, rattletrap, unsure, variant, fluid, runny, tippy, various, crank, uncertain, unpredictable, fantastic, parlous, freakish, strong, erratic, infirm, insane, explosive, changeable, equivocal, coseismal, doubtful, capricious, wobbly, change, precarious, unsettled, dizzy, tottery, steady, ticklish, mentally ill, unsound, shaky, fluent, irresolute, touch-and-go, liquid, thin-skinned, tender, giddy, thermolabile, top-heavy, whimsical, unbalanced, uneasy, cranky, fantastical, seismic, inconsistent, volatile, risky, weak, volcanic, fallacious, shifty, unfit, labile, insecure, seismal, temperamental, changeful.
changeable (part of speech: adjective)
- "Wisdom and Destiny", Maurice Maeterlinck.
- "From One Generation to Another", Henry Seton Merriman.
And all the while her mother was dreaming upon the first year of Hilda's life, before she had discovered that her husband's health was as unstable as his character, and comparing the reality of the present with her early illusions.- "Hilda Lessways", Arnold Bennett.