unjustifiable

From un- +‎ justifiable.

unjustifiable (comparative more unjustifiable, superlative most unjustifiable)

1. That cannot be justified, excused or pardoned.

   Synonyms: indefensible, inexcusable, unforgivable, unpardonable, unprovoked, unreasonable, regrettable, unacceptable, unworthy, remiss, blameworthy, culpable, unwarrantable, excessive, immoderate, unconscionable, outrageous, groundless, unfounded, foundationless, baseless, unsupported, unsubstantiated, unconfirmed, uncorroborated, invalid, untenable, weak, shaky, flawed, defective

   • 1962 October, G. Freeman Allen, “The New Look in Scotland's Northern Division—II”, in Modern Railways, page 270:

     From track level, its operating floor looks particularly capacious, but there is a vacant space at one end which was designed to accommodate the control panel for the Perth-Inverness C.T.C. scheme; this was adumbrated as long ago as the 1955 Modernisation Plan, but now seems to be regarded as an unjustifiable luxury.

• unjustifiability
• unjustifiableness
• unjustifiably