Rigid
WordNet
adjective
(1) Incapable of or resistant to bending
"A rigid strip of metal"
"A table made of rigid plastic"
"A palace guardsman stiff as a poker"
"Stiff hair"
"A stiff neck"
(2) Designating an airship or dirigible having a form maintained by a stiff unyielding frame or structure
(3) Incapable of adapting or changing to meet circumstances
"A rigid disciplinarian"
"An inflexible law"
"An unbending will to dominate"
(4) Fixed and unmoving
"With eyes set in a fixed glassy stare"
"His bearded face already has a set hollow look"- Connor Cruise O'Brien
"A face rigid with pain"
(5) Incapable of compromise or flexibility