Offense Intended?

I cracked up at this.

Most authors worry, at most, about libel suits, infringement, the usual legal hurdles. One piece of advice I've seen about portraying a character largely based on an acquaintance is to give the character a lot of extra afflictions (a scorching case of herpes, a secret homosexual lover, maybe terrible breath, offensive body odor, and a parent or child in prison/mental hospital). That way, the relatively innocuous things you've documented that might encourage a libel suit are offset by the person not wanting to announce that they may have all these other things wrong.

Also, with libel suits, you have to be proven to knowingly defame someone's character to their detriment, and in a case where the only defamation happened when they piped up, your chances are better, right? In theory, anyway.

But as with infringement/fair use issues, there's always an exception. Like when you get more than dirty looks from the people you've lampooned. It must be a pretty good book to inspire a lynch-mob.