The fallacies in this section are all cases where a word or phrase is used unclearly. There are two ways in which this can occur. (1) The word or phrase may be ambiguous, in which case it has more than one distinct meaning. (2) The word or phrase may be vague, in which case it has no distinct meaning.

An amphiboly occurs when the construction of a sentence allows it to have two different meanings.

Emphasis is used to suggest a meaning different from the actual content of the proposition.

The same word is used with two different meanings.