A
logical fallacy in which the
definition of a
term is self-
contradictory. This is a good way to tell if someone
has no idea what he's talking about.
Example: "Daytime is when you can see the sun and no stars." The sun is a star.
To prove that the definition is self-contradictory, proceed in a manner similar to that for Inconsistency: assume one condition of definition is true, and show that another must be false.