Synonyms of unstable in English:


See US English definition of unstable

See UK English definition of unstable

See Spanish definition of inestable


1‘icebergs are notoriously unstable and may flip over’

unsteady, rocky, wobbly, wobbling, rickety, shaky, tottery, tottering, teetering, doddery, unsafe, unbalanced, unreliable, insecure, not secure, unfastened, unsecured, movable, precarious
Irish bockety

stable, steady

2‘the country suffered from unstable coffee prices’

changeable, volatile, variable, unsettled, fluctuating, inconstant, inconsistent, irregular, fitful, unpredictable, unreliable, fickle, capricious, mercurial, erratic, uncertain, wavering
informal peaky

stable, firm

3‘he was mentally unstable’

unbalanced, of unsound mind, mentally ill, deranged, demented, crazed, distracted, troubled, disturbed, unhinged, insane, mad, mad as a hatter, mad as a March hare, raving mad, lunatic, out of one's head, out of one's mind, not in one's right mind, neurotic, psychotic
non compos mentis
British sectionable
informal crazy, loopy, loony, mixed up, nuts, nutty, nutty as a fruitcake, bananas, cracked, crackpot, dippy, screwy, bats, cuckoo, bonkers, mental, screwed up, not all there, off one's head, out to lunch, a bit lacking, round the bend
British informal daft, barmy, crackers, barking, barking mad, batty, dotty, potty, off one's rocker, off one's trolley, daft as a brush, not the full shilling, round the twist, away with the fairies
North American informal nutsy, nutso, squirrelly, wacko, buggy
dated touched

stable, balanced