self-opinionated
US /ˌself.əˈpɪn.jə.neɪ.tɪd/
UK /ˌself.əˈpɪn.jə.neɪ.tɪd/

1.
selbstgefällig, rechthaberisch, dogmatisch
having a high opinion of oneself or one's own opinions; conceited or dogmatic
:
•
His self-opinionated remarks often alienated his colleagues.
Seine selbstgefälligen Bemerkungen entfremdeten oft seine Kollegen.
•
She was too self-opinionated to consider other viewpoints.
Sie war zu selbstgefällig, um andere Standpunkte in Betracht zu ziehen.