rigid

adj

1.
incapable of or resistant to bending
stiff
Derived from:
rigidity rigidness
2.
incapable of compromise or flexibility
strict
Derived from:
rigidity rigidness
3.
incapable of adapting or changing to meet circumstances
inflexible unbending
Derived from:
rigidness
4.
designating an airship or dirigible having a form maintained by a stiff unyielding frame or structure
Antonym:
nonrigid
5.
fixed and unmoving
fixed set
Derived from:
rigidness