The adjective dogmatic means someone who is strongly expressing their beliefs as if they were facts.

Synonyms are assertive, dictatorial, intolerant, or stubborn.

The word origins from Late Latin (1680s) dogmaticus meaning “disposed to make positive assertions without presenting arguments or evidence”, and from Greek dogmatikos meaning “pertaining to doctrines”, from dogma meaning “opinion, tenet”, literally meaning “that which one thinks is true”, from dokein meaning “to seem good, think”.

The students are listening well if the lecture is dogmatic theology.

The dogmatic writer caught the interest of the readers.

His dogmatic decisions brought disaster in history.