1. Without a basis in reason or fact
   "unfounded suspicions"
   - baseless, groundless, idle, unwarranted, wild

See also: unsupported

• flapping
• flaps
• flare
• flare out
• flare pass
• flare path
• flare star
• flare-up
• flaring
• flash
• flash butt welding
• flash camera
• flash in the pan
• flash lamp
• flash memory
• flash welding
• flash-forward
• flash-freeze
• flash-frozen
• flashback
• flashboard
• flashboarding
• flashbulb
• flashcard
• flasher