Related Clues:

• Strict
• Set in stone
• Not subject to change
• Stupid person
• Binding, as a contract
• Changeless
• Stringently enforced
• Unchanging
• Stringently enforced, as a rule
• *Inviolable, as rules
• Impossible to change
• Invariable
• Fixed (like a bullet?)
• Rigidly applied
• (Of rules) invariable