1. A fictional material (either a metal or crystalline mineral) that has a detrimental effect on Superman

Encyclopedia: Kryptonite

• rigidify
• rigidifying
• rigidity
• rigidly
• rigidness
• Rigil
• Rigil Kent
• rigmarole
• rigor
• rigor mortis
• rigorism
• rigorist
• rigorous
• rigorously
• rigorousness
• rigour
• rigourousness
• rigout
• rijstafel
• rijstaffel
• rijsttaffel
• Riksmaal
• Riksmal
• rile
• riled