IPA: /ˈkaʊnsələr/
KK: /ˈkaʊnslər/
A person who is a member of a group that makes decisions or gives advice, especially in a local government or organization.
The councilor proposed a new plan to improve the community park.
Councilor → It is formed from "council" (from Old French *conseil*, meaning advice or consultation) and "-or" (meaning a person who). A councilor is a person who gives advice or participates in a council.
Think of a person who gives 'advice' ('council') — the '-or' indicates that this person is involved in that advisory role.