1. firm and stiff: not bending or easily moved into a different shape or position lengths of rigid plastic pipe
2. inflexible: applied or carried out strictly, with no allowances or exceptions a rigid set of rules
3. inflexibly adhered to: kept unchanged and strictly adhered to rigid opinions
4. refusing to change: unwilling to change or adapt behavior, opinions, or attitudes Despite arguments to the contrary, she remained rigid in her stand.
[15th century. < Latin rigidus< rigere "be stiff"]
