[ in-stuh-bil-i-tee ]
/ ˌɪn stəˈbɪl ɪ ti /


the quality or state of being unstable; lack of stability or firmness.
the tendency to behave in an unpredictable, changeable, or erratic manner: emotional instability.

Origin of instability

1375–1425; late Middle English instabilite < Latin instabilitās. See in-3, stability Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for instability

British Dictionary definitions for instability


/ (ˌɪnstəˈbɪlɪtɪ) /

noun plural -ties

lack of stability or steadiness
tendency to variable or unpredictable behaviour
physics a fast growing disturbance or wave in a plasma
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for instability



early 15c., from Middle French instabilite "inconstancy," from Latin instabilitatem (nominative instabilitas) "unsteadiness," from instabilis "unsteady," from in- "not, opposite of" (see in- (1)) + stabilis (see stable (2)).

Online Etymology Dictionary, © 2010 Douglas Harper