rigid

/ˈri-jəd/

Middle English rigide, from Latin rigidus, from rigēre to be stiff

adjective

  1. deficient in or devoid of flexibility

  2. appearing stiff and unyielding

  3. inflexibly set in opinion

rigid price controls

his face rigid with pain

rigid rigorous strict stringent mean extremely severe or stern. rigid implies uncompromising inflexibility. rigorous implies the imposition of hardship and difficulty.