Meaning of UNSTABLE in English


“+ adjective

Etymology: Middle English, from un- (I) + stable

: not stable: as


(1) : not firm or fixed in one place : apt to move : movable

snow as unstable as aspic trembled on the steep slope — R.L.Neuberger

the unstable shifting sands of the desert

(2) : lacking steadiness : apt to sway or fall

the tower proved to be unstable in a high wind

the bird flutters on its unstable pech

(3) : not steady in movement : irregular

felt the unstable tripping beat of her heart

(4) : not firm or substantial : weak , insecure

the young earth was yet unstable , the molten forces within were constantly looking for escape — W.E.Swinton

the road may become so unstable as to compel the imposition of a speed limit — O.S.Nock

built on an unstable foundation


(1) : wavering in purpose or intent : vacillating

an unstable and uneasy class of yeomen — S.E.Morison & H.S.Commager

his rather unstable religious convictions — H.E.Starr

woman's love … is volatile, insoluble, unstable — Marcia Anderson

(2) : exhibiting or characterized by emotional instability

an unstable temperament — Rex Ingamells

the unstable prisoners … placed in the vague but convenient category of psychopaths — A.H.MacCormick

had brought an inherently unstable nature to the point of mental and emotional collapse — E.J.Simmons


(1) : variable in character or condition : liable to change or alteration : changeable

an unstable world economy … subjected to periods of wars, inflation, and depression — Farmer's Weekly (South Africa)

the wind might change; for it is an unstable world — Charles Kingsley

unstable climate

unstable relationship

(2) : readily decomposing or changing otherwise in chemical composition or biological activity — compare labile 3, sensitive 4e

(3) : readily changing in physical state or properties

unstable emulsions tend to separate into layers

(4) : spontaneously radioactive

Synonyms: see inconstant

Webster's New International English Dictionary.      Новый международный словарь английского языка Webster.