wart
n. A small, crocky feature that sticks out of an
otherwise clean design. Something conspicuous for localized
ugliness, especially a special-case exception to a general rule.
For example, in some versions of `csh(1)', single quotes
literalize every character inside them except `!'. In ANSI C,
the `??' syntax used for obtaining ASCII characters in a foreign
environment is a wart. See also miswart.