For me there is a difference between using an inappropriate word or phrase to describe something -- like pain or fear and using it aggressively.
"Oh s***, I stubbed my toe!" is very different from, "You are full of s****."
Your child will see and hear these words used by family, other kids and even in the market or playground.
I'd identify them and tell your child the truthful definition (sure, you do not have to describe a sex act -- but that isn't really what the word means when used that way).
I would not let my kid use "stupid", "moron", or "retard" -- not to mention racial or sexist slurs. The only way it makes sense to her is to tell her exactly why.
I also think that having other words to describe our feelings gives us a better chance of being understood. If the 'f' word is the only descriptive in use, most of us think that the person isn't bright enough to come up with another word like "very".
Swear words have their place. You will use them. The point is that using them appropriately was learned by all of us. I knew better than to use those words in a job interview, in polite company, or to my students. I do not even have to think about it. It also has more impact because I swear only when I want to be heard!