D defs.my
Entry 2 senses Webster, 1913

Rigid

/rĭj'-əd/ · Rig·id · IPA /ˈɹɪd͡ʒ.ɪd/
01 a. Firm; stiff; unyielding; not pliant; not flexible.
  1. 1.
    Firm; stiff; unyielding; not pliant; not flexible.
    “Upright beams innumerable Of rigid spears.” Milton.
  2. 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.