councillor | counsellor

(1) A member of a council is a councillor,
(2) a person who gives guidance is a counsellor.

Etymology -
The word counsellor derives via Old French from the Latin consiliare, to counsel or advise.
According to the OED, the word councillor was coined as: "An alteration of the earlier word counsellor, through assimilation to council. When counsel …, in the sense of an advising or deliberative body, came to be spelt council, counsellor … in the sense of a member of such a body was conformably spelt councillor."

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