Foul Language in Fiction -- Author vs. Character

[Mr Nobody]

Like others have said, it has to stay in character. Regardless of how kindly he is, vocabulary and means of expression would come down to the usual things: class, upbringing, etc. It also sounds like it'd be an extreme usage vented in anger at a hated, despised person. Sorry, but 'you nasty old thing' didn't cut it when the world was in black and white, and it won't cut it now because it sounds so phony.
The word, in this case, would not only contain everything the old man felt, but would be a smack across the chops for recipient and reader alike - so, go ahead...but only if it really is in character.

[w666]

Steve addresses this point eloquently in "On Writing"....so well, in fact, that it needs no further debate once you grasp his point. I don't recall it verbatim, however, so I'll go dig up the reference and post it later.

[w666]

For the AR amongst us, please refer to your HC version of "On Writing". Go to "-7-" (page 180) of the section titled "On Writing", following the section called "Toolbox".

[michal]

I personally would hate it if all the characters sound the same or reflect the same moral/ beliefs/ style/ level of education/ verbal similarity. To quote Mark Twain - "If all men thought alike we wouldn't have horse racing" and let me add: If all characters spoke and acted alike, we wouldn't have good stories. Let them act like they are -they are of your creation, but not necessarily you.