stable

1 marked by the ability to withstand stress without structural damage or distortion the observation tower is stable enough to withstand the strongest winds without collapsing Synonyms bombproof, fast, firm, sound, stalwart, strong, sturdy Related Words dependable, durable, reliable; infrangible, irrefragable, unbreakable; beefy, solid; cohesive, tough Near Antonyms infirm, insecure, weak; shaky, tottering, tottery, unbalanced, wobbly (also wabbly); unsubstantial Antonyms rickety, unsound, unstable, unsteady

2 having been established and usually not subject to change a troubled nation badly in need of a stable government Synonyms certain, determinate, final, firm, flat, frozen, hard, hard-and-fast, inexpugnable, set, settled, fixedRelated Words nonadjustable, noncancelable, nonnegotiable, unchangeable; constant, steady, unchanging, uniform, unwavering; definite, exact, explicit, specific; given, stated, stipulated; dependable, good, reliable, responsible, safe, solid, sure, tried, tried-and-true, true, trustworthy, trustyNear Antonyms adjustable, changeable, negotiable; indefinite, open-ended, unspecified; capricious, changeful, flickery, fluctuating, fluid, inconstant, mercurial, mutable, temperamental, uncertain, unpredictable, unsettled, unstable, unsteady, variable, volatile

3 having full use of one's mind and control over one's actions she made some strange decisions back when she wasn't entirely stable Synonyms balanced, clearheaded, compos mentis, lucid, normal, right, saneRelated Words analytic (or analytical), clear, coherent, logical, rational, reasonable; even-keeled, judicious, levelheaded, sensible, wise; healthy, sound, unneurotic; well-adjusted, well-balancedNear Antonyms balmy, bananas, batty, bughouse [slang], certifiable, crackbrained, cracked, crackpot, cranky [dialect], cuckoo, daffy, daft, dotty, fruity [slang], gaga, loco [slang], loony (also looney), loopy, meshuga (or meshugge also meshugah or meshuggah), moonstruck, nuts, nutty, scatty [chiefly British], screwy, wacko (also whacko), wacky (also whacky); aberrant, delirious, disordered; delusional, delusionary, disturbed, neurotic, obsessive-compulsive, paranoiac (also paranoic), paranoid (also paranoidal), psycho, psychotic, schizo, schizoid, schizophrenic, schizy (or schizzy); eccentric, odd, oddball, off, pixilated (also pixillated), potty [chiefly British], queer, strange; foolish, senseless, witless; irrational, mixed-up, unreasonable; depressed, despondent; distracted, distraught, frantic, frenzied, haywire, hysterical (also hysteric), raving, wigged-out; amok (or amuck), ape, ballistic, berserk, nuclear; fixated, monomaniac, monomaniacal, obsessedAntonyms brainsick, crazed, crazy, demented, deranged, insane, lunatic, mad, maniacal (also maniac), mental, unbalanced, unsound

4 not undergoing a change in condition a stable economic climate is best for business Synonyms changeless, constant, stationary, steady, unchanging, unvaryingRelated Words fast, fixed, hard-and-fast, immutable, inflexible, invariable, unalterable, unchangeable; established, set, settled; ceaseless, continuing, durable, enduring, lasting, permanentNear Antonyms adaptable, alterable, changeable, flexible, mutable, variable; ephemeral, evanescent, fleeting, momentary, transient, transitory; kaleidoscopic, phantasmagoric (or phantasmagorical)Antonyms capricious, changeful, changing, fickle, fluctuating, fluid, inconstant, mercurial, skittish, uncertain, unpredictable, unsettled, unstable, unsteady, varying, volatile