unable to bend or be bent; stiff
fixed in appearance
a face rigid with pain
having the outer shape maintained by a fixed framework
inflexibly set in opinions or habits
strictly maintained; unable to be changed
a rigid schedule
precise and accurate in procedure
rigidity /riʹjiditi/ noun
rigidly adv
rigidness noun
[Middle English via French from Latin rigidus, from rigēre to be stiff]