Definition of "improvable"

improvable¹

adjective
comparative more improvable, superlative most improvable
1. Capable of being improved.
  Quotations
  Therefore, Humanitarians alone devote their present lives to create heavens within themselves and others, and a real paradise upon earth, because they do not waste their time with Pagan delusions, Sceptical doubts, and Atheistical selfishness, but live happily in the present by preparing for themselves and others happier future human lives upon our improveable globe.
  1876, Joachim Kaspary, Natural Laws; or The Infallible Criterion, London: J. A. Brook & Co., […], page 136
2. Capable of being used to advantage; profitable.

improvable²

adjective
not comparable
1. Impossible to prove.