A more thorough explanation:

Definition: Something that is not what it seems; a counterfeit. A person who pretends to be something that he or she is not; a faker.

Examples:

• A fake designer handbag is a sham because it is not a real designer handbag.
• A person who claims to be a doctor but has no medical degree is a sham because they are pretending to be something they are not.

These examples illustrate the definition of sham because they both involve something or someone pretending to be something they are not. The fake designer handbag is a sham because it is not a genuine designer handbag, even though it may look like one. The person pretending to be a doctor is a sham because they are not qualified to practice medicine, even though they may be trying to convince others that they are.