Why is equivocation a fallacy?

Equivocation is a fallacy because it is a form of argumentation that is both misleading and logically unsound. When the meaning of a word or phrase shifts in the course of an argument, it causes confusion and also implies that the conclusion (which may be true) does not follow from the premise.

The equivocation fallacy is an informal logical fallacy, meaning that the error lies in the content of the argument instead of the structure.