not flexible; incapable of or resistant to being bent; rigid:an inflexible steel rod.2.of a rigid or unyielding temper, purpose, will, etc.; immovable:an inflexible determination.3.not permitting change or variation; unalterable:inflexible rules.
having, assuming, or passing through many or various forms, stages, or the like.2.polymorphic.Origin of polymorphous