councillor; councilor; advisor
An official title for a person serving in an advisory capacity, often in a governmental or organizational context. The term is somewhat formal and may be encountered in historical or institutional settings.
He was appointed as a councillor to the cabinet.
Compound of 顧問 (komon, 'advisor') and 官 (kan, 'official'). The exact historical derivation is uncertain, but the term likely emerged in the Meiji era as a formal title for government advisors.