rigid

UK: /ˈrɪdʒɪd/ US: /ˈrɪdʒɪd/ ,(rij′id)

WordReference Random House Learner's Dictionary of American English © 2025

rig•id /ˈrɪdʒɪd/   adj. 

1. stiff;
   not easily moved:
   a rigid strip of metal.
2. fixed in one's thinking:
   He can be very rigid when it comes to rules.
3. strict or severe:
   The rules are too rigid.

rig•id•ly, adv.: 

He stood rigidly at attention.

rig•id•ness, n. [uncountable]

WordReference Random House Unabridged Dictionary of American English © 2025

rig•id  (rij′id), adj. 

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, Physics of, pertaining 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
   • (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.

• Latin rigidus, equivalent. to rig(ēre) to be stiff, stiffen + -idus -id⁴
• 1530–40

ri•gid′i•ty, rig′id•ness, n. 
rig′id•ly, adv. 
Synonyms

• 1. unbending, firm, inflexible.
• 2. immovable, static.
• 3. austere, stern, unyielding. See strict. 
• 4, 5. demanding.

Antonyms

• 1. elastic.
• 3. lax.

Collins Concise English Dictionary © HarperCollins Publishers::

rigid / ˈrɪdʒɪd/ adjective

1. not bending; physically inflexible or stiff: a rigid piece of plastic
2. unbending; rigorously strict; severe: rigid rules

Etymology: 16th Century: from Latin rigidus, from rigēre to be stiff

ˈrigidly adverb

riˈgidity, ˈrigidness noun