A person who allows something (in various senses of the verb).

A person who confirms, sanctions, pronounces good, or commends.

A person who admires something or someone.

One who formally approves or sanctions; an approver.

colloquial. (a) one for ——: a person who likes, practises, or supports (something), esp. to an outstanding degree; a devotee, champion, or admirer…

A person who reconciles people or things; a mediator. Also: a person who agrees with something.