Yep, we'd accept "f***king" as one word. You did right in putting in the asterisks like that, but in fact if you hadn't, it would have been (well, should have been...) wholly asterisked out by the software, ie ******* which I find makes it less impressive as a cuss word!
But do make sure that it really is the offender in pushing you over word count -- I've just checked and as I suspected Word treats the asterisked version as one word so it shouldn't make a difference.
Just to remind everyone, always be careful of hyphenated words or neologisms and get confirmation from a mod about them before posting. And never rely on Word or anything else -- always count by hand by way of a double check!