Antonyms of adj unstable

6 senses of unstable

Sense 1
unstable (vs. stable) -- (lacking stability or fixity or firmness; "unstable political conditions"; "the tower proved to be unstable in the high wind"; "an unstable world economy")

stable (vs. unstable) -- (resistant to change of position or condition; "a stable ladder"; "a stable peace"; "a stable relationship"; "stable prices")
        => firm, steady, unfluctuating -- (not liable to fluctuate or especially to fall; "stocks are still firm")
        => lasting -- (lasting a long time without change; "a lasting relationship")
        => stabile -- ((chemistry, physics, biology) resistant to change)
        => stabilized, stabilised -- (made stable or firm)

Sense 2
unstable -- (highly or violently reactive; "sensitive and highly unstable compounds")

INDIRECT (VIA reactive) -> unreactive -- ((chemistry) not reacting chemically)

Sense 3
precarious, unstable -- (affording no ease or reassurance; "a precarious truce")

INDIRECT (VIA uneasy) -> easy -- (free from worry or anxiety; "knowing that I had done my best, my mind was easy"; "an easy good-natured manner"; "by the time the chsild faced the actual problem of reading she was familiar and at ease with all the elements words")

Sense 4
mentally ill, unsound, unstable -- (suffering from severe mental illness; "of unsound mind")

INDIRECT (VIA insane) -> sane -- (mentally healthy; free from mental disorder; "appears to be completely sane")

Sense 5
unstable -- (disposed to psychological variability; "his rather unstable religious convictions")

INDIRECT (VIA irresolute) -> resolute -- (firm in purpose or belief; characterized by firmness and determination; "stood resolute against the enemy"; "faced with a resolute opposition"; "a resolute and unshakeable faith")

Sense 6
fluid, unstable -- (subject to change; variable; "a fluid situation fraught with uncertainty"; "everything was unstable following the coup")

INDIRECT (VIA changeable) -> unchangeable -- (not changeable or subject to change; "a fixed and unchangeable part of the germ plasm"-Ashley Montagu; "the unchangeable seasons"; "one of the unchangeable facts of life")

Similarity of adj unstable

6 senses of unstable

Sense 1
unstable (vs. stable) -- (lacking stability or fixity or firmness; "unstable political conditions"; "the tower proved to be unstable in the high wind"; "an unstable world economy")
       => coseismic, coseismal -- (being where earthquake waves arrive simultaneously)
       => crank, cranky, tender, tippy -- ((used of boats) inclined to heel over easily under sail)
       => explosive, volatile -- (liable to lead to sudden change or violence; "an explosive issue"; "a volatile situation with troops and rioters eager for a confrontation")
       => rickety, shaky, wobbly, wonky -- (inclined to shake as from weakness or defect; "a rickety table"; "a wobbly chair with shaky legs"; "the ladder felt a little wobbly"; "the bridge still stands though one of the arches is wonky")
       => rocky -- (liable to rock; "on high rocky heels")
       => seismic, seismal -- (subject to or caused by an earthquake or earth vibration)
       => tipsy -- (unstable and prone to tip as if intoxicated; "a tipsy boat")
       => top-heavy -- (unstable by being overloaded at the top)
       => tottering -- ((of structures or institutions) having lost stability; failing or on the point of collapse; "a tottering empire")
       => volcanic -- (explosively unstable; "a volcanic temper")
          Also See-> impermanent#1, temporary#1; inconstant#1; unsteady#1

Sense 2
unstable -- (highly or violently reactive; "sensitive and highly unstable compounds")
       => reactive (vs. unreactive) -- (participating readily in reactions; "sodium is a reactive metal"; "free radicals are very reactive")

Sense 3
precarious, unstable -- (affording no ease or reassurance; "a precarious truce")
       => uneasy (vs. easy) -- (lacking a sense of security or affording no ease or reassurance; "farmers were uneasy until rain finally came"; "uneasy about his health"; "gave an uneasy laugh"; "uneasy lies the head that wears the crown"; "an uneasy coalition government"; "an uneasy calm"; "an uneasy silence fell on the group")

Sense 4
mentally ill, unsound, unstable -- (suffering from severe mental illness; "of unsound mind")
       => insane (vs. sane) -- (afflicted with or characteristic of mental derangement; "was declared insane"; "insane laughter")

Sense 5
unstable -- (disposed to psychological variability; "his rather unstable religious convictions")
       => irresolute (vs. resolute) -- (uncertain how to act or proceed; "the committee was timid and mediocre and irresolute")

Sense 6
fluid, unstable -- (subject to change; variable; "a fluid situation fraught with uncertainty"; "everything was unstable following the coup")
       => changeable (vs. unchangeable), changeful -- (such that alteration is possible; having a marked tendency to change; "changeable behavior"; "changeable moods"; "changeable prices")