confusion
Fireproof Foolproof
forgetful
formality frequency fairyland fusillade
Forgetful.
A nine letter word using those letters is foresight.
Those letters will spell fragrance.
A five letter word, second letter F is after or often.
No English Scrabble words meet the criteria, whether you interpret the "you" as an I or a U.
An example of a word that contains the letter "f" as the letter "e" is "caffeine."
All depends what the clue is, may be Frederick or Firebrick
Finish is another word for completion starting with the letter F.
The opposite for the word plain starting with letter f is FANCY.