Noah Webster's Dictionary 1. (a.) Firm; stiff; unyielding; not pliant; not flexible. 2. (a.) Hence, not lax or indulgent; severe; inflexible; strict; as, a rigid father or master; rigid discipline; rigid criticism; a rigid sentence.

Multi-Version Concordance Rigid (1 Occurrence) Mark 9:18 and wherever it seizes him, it throws him down, and he foams at the mouth, and grinds his teeth, and wastes away. I asked your disciples to cast it out, and they weren't able." (See RSV NIV)