What double meaning does the word leech have?

Leech can refer to:

A leech, an aquatic worm that feeds on the blood of other animals.

A person who clings to someone or something for personal advantage.

In the first sense, the word is used literally to refer to a type of worm. In the second sense, it is used metaphorically to refer to a person who takes advantage of others.

For example:

The patient was treated for anemia caused by a leech infestation.

The politician was accused of being a leech on the taxpayers.

In the first example, the word leech is used literally to refer to a worm. In the second example, it is used metaphorically to refer to a politician who takes advantage of taxpayers.