disobligatory

From dis- +‎ obligatory.

disobligatory (not comparable)

1. (obsolete) Releasing from obligation.
   • June 6, 1646, Charles I of England, To Mr. Alan Henderson

     And you much mistake in alledging that the two Houses of Parliament (especially as they are now constituted) can have this Disobligatory power […]

• “disobligatory”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.