1. Retarded in intellectual development
   - backward, slow-witted, feebleminded

See also: retarded

• fiber-optic transmission system
• fiberboard
• fiberglass
• fiberoptic
• fiberoptics
• fiberscope
• Fibonacci number
• Fibonacci sequence
• fibre
• fibre bundle
• fibre optic cable
• fibre-optic transmission system
• fibreboard
• fibreglass
• fibreoptic
• fibreoptics
• fibrescope
• fibril
• fibrillar
• fibrillate
• fibrillation
• fibrillose
• fibrin
• fibrinase
• fibrinogen