The definition of deceptive is something that is misleading or that is presenting a lie.(adjective)
An advertisement that presents untrue facts about the product is an example of an ad that would be described as deceptive.
See deceptive in Webster's New World College Dictionary
Origin: Fr déceptif < LL deceptivus: see deceive & -ive
See deceptive in American Heritage Dictionary 4
Learn more about deceptive