Noah Webster's Dictionary 1. (a.) Exact; strict; severe; relentless; uncompromising; manifesting, exercising, or favoring rigor; allowing no abatement or mitigation; scrupulously accurate; as, a rigorous officer of justice; a rigorous execution of law; a rigorous definition or demonstration. 2. (a.) Severe; intense; inclement; as, a rigorous winter. 3. (a.) Violent.

Multi-Version Concordance Rigorous (2 Occurrences) Daniel 2:15 he answered and said to Arioch the king's captain, Why is the decree so rigorous from the king? Then Arioch made the thing known to Daniel. (DBY) Daniel 3:22 Forasmuch as the king's commandment was rigorous, and the furnace exceeding hot, the flame of the fire slew those men that had taken up Shadrach, Meshach, and Abed-nego. (DBY)