Rigid

Part of speech: adjective (a.)

1. Firm; stiff; unyielding; not pliant; not flexible. Upright beams innumerable Of rigid spears. Milton.

2. Hence, not lax or indulgent; severe; inflexible; strict; as, a rigid father or master; rigid discipline; rigid criticism; a rigid sentence. The more rigid order of principles in religion and government. Hawthorne.

Synonyms: Stiff; unpliant; inflexible; unyielding; strict; exact; severe; austere; stern; rigorous; unmitigated.