Sophism can mean two very different things. In Ancient Greece, sophism was practiced by sophists, who were a group of teachers of philosophy and rhetoric. In the modern definition, a sophism is a confusing or slightly incorrect argument used for deceiving someone.
The similar Greek word σοφιστής, "sophistēs" means "wise-ist, one who does wisdom, one who makes a business out of wisdom" while σοφός, "sophós" means a "wise man".
The ancient Greek philosopher Protagoras (ca. 490–420 BC) is often said to be the first of the sophists. Others include: Gorgias, Prodicus, Hippias, Thrasymachus, Lycophron, Callicles, Antiphon, and Cratylus.
A sophism is a statement to deceive someone in a debate or conversation. It might be made to seem to make sense when really being wrong, or it might use difficult words and complicated sentences to intimidate the audience into agreeing. An argument ad hominem is an example of sophistry.
A sophist is a person who uses sophisms. Sophistry means using sophisms for subtly deceptive reasoning or argumentation.