unwarrantable

From un- +‎ warrantable.

unwarrantable (comparative more unwarrantable, superlative most unwarrantable)

1. Not warrantable; indefensible; not vindicable; not justifiable
   • 1661, Joseph Glanvill, The Vanity of Dogmatizing, London: Henry Eversden, Chapter 15, pp. 136-137,

     Another thing, that engageth our affections to unwarrantable conclusions, and is therefore fatal to Science; is our doting on Antiquity, and the opinions of our Fathers.

   • 1776, Thomas Paine, Common Sense, Philadelphia, “The Necessity of Independancy,” p. 70,

     […] the taking up arms, merely to enforce the repeal of a pecuniary law, seems as unwarrantable by the divine law, and as repugnant to human feelings, as the taking up arms to enforce the obedience thereto.

   • 1847, Emily Brontë, Wuthering Heights, Chapter 14,

     ‘ […] Don’t persist, sir! or else I shall be obliged to inform my master of your designs; and he’ll take measures to secure his house and its inmates from any such unwarrantable intrusions!’

   • 1912, Sir Arthur Conan Doyle, The Lost World‎:

     After this unwarrantable invasion, which not only filled every passage, but even intruded upon the space set apart for the Press, it is estimated that nearly five thousand people awaited the arrival of the travelers.

   Synonyms: illegal, unjust, improper

• unwarrantable in The Century Dictionary, New York, N.Y.: The Century Co., 1911
• unwarrantable in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913