Equivocation is a form of logical fallacy where an argument is made that uses different meanings of a word as though they were the same. An example would be something like this:
1. Sharp things cause balloons to pop.
2. John is a really sharp dresser.
3. Therefore, John causes balloons to pop.
Two different meanings of the word “sharp” are being confused, which causes us to come to a false conclusion. The fact that John dresses handsomely (making him a “sharp” dresser) doesn’t mean he pops balloons. Here, the metaphorical, idiomatic definition of sharp (“sharp dresser”) is confused with literal sharpness.