I am by no means an expert, but as a radio listener, especially during the 90's I found that the most commonly used methods are replacing the offending word with a cleaner one, or silence in the vocal track during the offensive word (I have heard the entire song go silent for that word as well). The silence can be really weird and jarring if the whole word is cut. In my opinion this is best achieved by removing only enough of the word that it's not technically present, but there is enough to allow the mind to recreate it. I agree with you though that a tone over the word would be a bit aggressive. Reversing it might work, but it's still there so there is some risk. I would try a creative edit to replace the word with another one that is present somewhere in the track; however, I think much of this is going to come down to what is preferred by the client and label (if applicable). The partial silence might be a good fall back option if there isn't anything that can fit the cadence and rhyme scheme.
In the few projects I have done that wanted 'radio' friendly versions of songs we just tracked a clean and regular vocal line for those sections and printed a separate clean mix. This way we were able to get a 'clean' word in the lyric that flowed with the rest of the lyrics for that version.