1. Totally unlikely
   - impossible, inconceivable, unimaginable

See also: unthinkable

• guesswork
• guest
• guest night
• guest of honor
• guest of honour
• guesthouse
• guestimate
• guestroom
• guestworker
• Guevara
• Guevina
• Guevina avellana
• Guevina heterophylla
• guff
• guffaw
• Guggenheim
• guggle
• Guglielmo Marconi
• GUI
• Guiana
• Guiana Highlands
• guib
• Guibert of Ravenna
• guidable
• guidance