rigidity

adjective

1. stiff or unyielding; not pliant or flexible; hard: a rigid strip of metal.
2. firmly fixed or set.
3. inflexible, strict, or severe: a rigid disciplinarian; rigid rules of social behavior.
4. exacting; thorough; rigorous: a rigid examination.
5. so as to meet precise standards; stringent: lenses ground to rigid specifications.
6. 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.
7. Aeronautics.
   1. (of an airship or dirigible) having a form maintained by a stiff, unyielding structure contained within the envelope.
   2. pertaining to a helicopter rotor that is held fixedly at its root.

adjective

1. not bending; physically inflexible or stiffa rigid piece of plastic
2. unbending; rigorously strict; severerigid rules

adverb

3. completely or excessivelythe lecture bored him rigid

n.

1620s, from Latin rigiditas “stiffness,” from rigidus (see rigid).

adj.

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.

n.

1. The quality or state of stiffness or inflexibility.rigor
2. An aspect of the personality characterized by resistance to change.