Instabile

Instabile is an Italian adjective meaning not stable, precarious, or unreliable. It describes something lacking steadiness, balance, or predictability, and can be applied to physical objects, processes, systems, situations, or emotions. In everyday language it can refer to unstable relationships or markets, as well as to a person who is emotionally or mentally unstable. In science, it is used for states or structures that may change or decay, such as an unstable nucleus or an unstable chemical compound.

Etymology and grammar: Instabile derives from Latin instābilis, via the family of Romance languages that give rise to the modern Italian form. In Italian, adjectives ending in -e have the same form for masculine and feminine in the singular, and form the plural with -i (instabili). For example, una tavola instabile, due strutture instabili, una situazione instabile.

Usage and contexts: The term is common across domains. Physically, it can describe a tilted, unsafe, or precarious object or structure. In science, it refers to systems that are not in a stable state, such as isotopes that decay (isotopi instabili). In social and economic discourse, it characterizes volatile or unpredictable conditions, for instance an unstable market or an unstable political situation. It can also describe personal states—someone who feels unstable emotionally or psychologically.

Related terms: stability (stabilità) and stable (stabile). The noun form instabilità denotes instability, the abstract quality of lacking steadiness.