How do I replace F*** while expressing fully my disbelief, anger, etc?
"I think Homer Simpson is incredibly sexy"
My reply "Get out of here! That's f***ing ridiculous."
Besides RegDwight’s excellent suggestions, flaming and frigging are both widely used (respectively more common in the UK and US, I think).
In my family, when I was small, my father would always say “That’s ff… frankly ridiculous,” and so on — going completely over my head at the time, and much to the amusement of the adults around. “Shiver me timbers!” was another favourite exclamation of his, for similar reasons…
It’s easy to vary the subtlety/blatantness of these, and hence to sound completely innocuous to outsiders while ensuring that your friends know what you’re really thinking :-)
Since I watched Battlestar Galactica (the new series), I've been using 'frakking' a lot.
Verbally I prefer French foutu.
It is, by the way, printable word. One can find it in lyrics, for example, in
Le Temps Des Cathédrales - Bruno Pelletier - Notre-Dame de Paris (comédie musicale)
In internet (chat, twitter, Email) I usually give/insert the link to multi-media "Polar Bear"
See also my related question "How would you substitute English vulgar words in foreign phrases?"
I agree with JasonFruit's answer, and will add another option:
Get out of here! That's completely ridiculous.
The word completely works here, though not in all contexts. Having to think of an appropriate adverb (or, sometimes, other word) in a given context will provide good exercise for your brain.