- stiff or unyielding; not pliant or flexible; hard: a rigid strip of metal.
- firmly fixed or set.
- inflexible, strict, or severe: a rigid disciplinarian; rigid rules of social behavior.
- exacting; thorough; rigorous: a rigid examination.
- so as to meet precise standards; stringent: lenses ground to rigid specifications.
- Mechanics. of, relating to, or noting a body in which the distance between any pair of points remains fixed under all forces; having infinite values for its shear modulus, bulk modulus, and Young’s modulus.
- (of an airship or dirigible) having a form maintained by a stiff, unyielding structure contained within the envelope.
- pertaining to a helicopter rotor that is held fixedly at its root.
- not bending; physically inflexible or stiffa rigid piece of plastic
- unbending; rigorously strict; severerigid rules
- completely or excessivelythe lecture bored him rigid
early 15c., from Latin rigidus “hard, stiff, rough, severe,” from rigere “be stiff,” from PIE *reig- “stretch (tight), bind tightly, make fast” (cf. Old Irish riag “torture,” Middle High German ric “band, string”). Related: Rigidly.