From Greek 'dogmatikos' (pertaining to doctrines) — a neutral philosophical term that became an insult for rigid thinking.
Inclined to lay down principles as incontrovertibly true; asserting opinions in an arrogant or authoritative manner without consideration of evidence or the opinions of others.
From Late Latin 'dogmaticus,' from Greek 'dogmatikos' (δογματικός), meaning pertaining to doctrines, from 'dogma' (δόγμα, genitive 'dogmatos'), meaning opinion, tenet, decree. Greek 'dogma' derives from 'dokein' (δοκεῖν), meaning to seem, think, or suppose, from Proto-Indo-European *deḱ- (to take, accept, perceive). In ancient philosophy, 'dogmatikoi' (Dogmatists) were philosophers who asserted positive doctrines, as opposed to the Skeptics who suspended
Greek 'dogma' comes from 'dokein' (to seem, think), the same root that produced 'orthodox' (right-seeming, correct opinion), 'paradox' (against what seems true), 'doctor' (Latin 'docēre,' to teach — one who makes things seem clear), and 'decent' (Latin 'decēre,' to be fitting — what seems right). A dogmatist and a doctor are etymological cousins: both deal in what seems to be true.