say it: in-stuh-BIL-i-tee
instability is a noun meaning "an unstable order". It carries 4 recorded senses.
unreliability attributable to being unstable
the quality or attribute of being unstable and irresolute
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for instability 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.