fuddy-duddy
- n a conservative who is old-fashioned or dull in attitude or appearance
you may accuse me of being and old fuddy-duddy trying to stop young people having fun
fuckup
- n someone who makes mistakes because of incompetence
- n an embarrassing mistake
fucoid
- n a fossilized cast or impression of algae of the order Fucales
- n any of various algae of the family Fucaceae