Source : Webster's Revised Unabridged Dictionary (1913)

Impermanent \Im*per"ma*nent\, a.
   Not permanent.

Source : WordNet®

impermanent
     adj 1: not permanent; not lasting; "politics is an impermanent
            factor of life"- James Thurber; "impermanent palm
            cottages"; "a temperary arrangement"; "temporary
            housing" [syn: {temporary}] [ant: {permanent}]
     2: existing or enduring for a limited time only