[1] : The Collaborative International Dictionary of English v.0.48

impermanent \imper"manent\, a.
   not permanent.
   1913 webster

[2] : WordNet (r) 2.0

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
see also:
temporary permanent 

[3] : Moby Thesaurus II by Grady Ward, 1.0

64 moby thesaurus words for "impermanent":
   able to adapt, adaptable, adjustable, alterable, alterative,
   brittle, capricious, changeable, checkered, corruptible, deciduous,
   dying, ephemeral, evanescent, ever-changing, fading, fickle,
   fleeting, flexible, flitting, fluid, fly-by-night, flying, fragile,
   frail, fugacious, fugitive, impetuous, impulsive, inconstant,
   insubstantial, kaleidoscopic, malleable, many-sided, metamorphic,
   mobile, modifiable, momentary, mortal, movable, mutable,
   nondurable, nonpermanent, nonuniform, passing, perishable,
   permutable, plastic, protean, proteiform, resilient, rubbery,
   short-lived, supple, temporal, temporary, transient, transitive,
   transitory, undurable, unenduring, unstable, variable, volatile

Impermanent >> I Words
Impermanent, definition of term: Impermanent
impermanent_pag1.html