say it: uhn-STAY-buhl
unstable is an adjective meaning "lacking stability or fixity or firmness". It carries 6 recorded senses.
subject to change; variable
“a fluid situation fraught with uncertainty”
“everything was unstable following the coup”
Definitions, synonyms and semantic relations for unstable come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.