sophistry

The original Sophists were ancient Greek teachers of rhetoric and philosophy prominent in the 5th century B.C. In their heyday, these philosophers were considered adroit in their reasoning, but later philosophers (particularly Plato) described them as sham philosophers, out for money and willing to say anything to win an argument. Thus sophist (which comes from Greek sophistēs, meaning "wise man" or "expert") earned a negative connotation as "a captious or fallacious reasoner." Sophistry is reasoning that seems plausible on a superficial level but is actually unsound, or reasoning that is used to deceive.