WordWeb Online

1. Not permanent; not lasting
   "politics is an impermanent factor of life"; "impermanent palm cottages";
   - temporary
    
2. Existing or enduring for a limited time only

See also: acting, ephemeral, episodic, episodical, evanescent, finite, fly-by-night, fugacious, here today and gone tomorrow [informal], here today gone tomorrow [informal], improvised, interim, jury-rigged, makeshift, passing, permanence, permanency, pro tem, pro tempore, shipboard, short-lived, temporal, terminable, transient, transitory, unstable, working

Encyclopedia: Impermanent