dogmatic
Concise Oxford English Dictionary © 2008 Oxford University Press:
dogmatic /dɒgˈmatɪk/
▶adjective inclined to assert principles or opinions as incontrovertibly true.
– derivatives
dogmatically adverb,
dogmatism noun,
dogmatist noun.
dogmatically adverb,
dogmatism noun,
dogmatist noun.
'dogmatic' also found in these Oxford entries:

