Well-heeled means rich — but it carries a particular flavour that plain "rich" does not. It describes people who look and live like they have money: good clothes, good address, the ability to write a cheque without thinking. You use it about a person, a family, or a group — "a well-heeled crowd", "her well-heeled parents", "the well-heeled suburbs north of the city". It is a slightly literary, slightly journalistic word. You will meet it in newspapers and magazines far more often than in conversation; nobody in Taiwan will say "my uncle is well-heeled" out loud, they will say "my uncle is rich". Because of that, it sits at a mild distance from the person described. It is not an insult, but it is not warm either. Often there is a small dry edge to it, a hint that the writer is standing outside looking in — "the museum's well-heeled donors" says something about a social class, not just a bank balance. It is almost always used before a noun. It has no comparative form people actually use, and there is no verb or noun built from it.