unconscionable

Etymology

un- + conscionable

adj

1. Not conscionable; unscrupulous and lacking principles or conscience.
   When Roger assured him that prospects "looked very good" for a retrial, even a reversal of the verdict, since Roger had discovered "unconscionable errors" in the trial, Jackson grunted in bemusement and smiled with half his mouth. 2001, Joyce Carol Oates, Middle Age: A Romance, paperback edition, Fourth Estate, page 364
2. Excessive, imprudent or unreasonable.
   The effective rate of interest was unconscionable, but not legally usurious.
   … and the agrieved person shall doe more manly, to be extraordinary and singular in claiming the due right whereof he is frustrated, then to piece up his lost contentment by visiting the Stews, or stepping to his neighbours bed, which is the common shift in this mis-fortune, or els by suffering his usefull life to wast away and be lost under a secret affliction of an unconscionable size to humane strength. 1643, John Milton, Doctrine and Discipline of Divorce