Heresy is proposing or teaching an opinion that is contrary to the validity of established doctrine, also known as dogma. Dogma is typically religious in nature but may be any orthodox set of beliefs. This doctrine may be the result of long-held tradition or may be codified into law.
Some cultures view heresy as a crime.
The Voth Ministry of Elders charged Professor Forra Gegen with the crime of heresy for teaching Distant Origin Theory, a scientific theory that challenged Voth religious doctrine. Despite the evidence standing before them, Professor Gegen was still found guilty. (VOY: "Distant Origin")