improvable

From improve +‎ -able.

improvable (comparative more improvable, superlative most improvable)

1. Capable of being improved.
   • 1876, Joachim Kaspary, Natural Laws; or The Infallible Criterion, London: J. A. Brook & Co., […], →OCLC, page 136:

     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.

2. Capable of being used to advantage; profitable.

   Synonyms: serviceable, advantageous

• improveable

• improvableness
• improvably

From im- +‎ provable.

improvable (not comparable)

1. Impossible to prove.

• improvably

• improbable

• “improvable”, in The Century Dictionary […], New York, N.Y.: The Century Co., 1911, →OCLC.
• “improvable”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.