rigid

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"

incapable of compromise or flexibility

incapable of adapting or changing to meet circumstances; "a rigid disciplinarian"; "an inflexible law"; "an unbending will to dominate"

designating an airship or dirigible having a form maintained by a stiff unyielding frame or structure

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"