1. Impossible to achieve
   - unachievable, unattainable, undoable, unrealizable

See also: impossible

• fend off
• fender
• fender-bender
• fenestella
• fenestra
• fenestra cochleae
• fenestra of the cochlea
• fenestra of the vestibule
• fenestra ovalis
• fenestra rotunda
• fenestra vestibuli
• fenestral
• fenestrate
• fenestrated
• fenestration
• feng-shui
• Fengtien
• Fenian
• fenland
• fennec
• fennel
• fennel flower
• fennel seed
• Fennic
• fenny