A person acting as the public face of some other, covert group.
The lead singer in a musical group.
striker, attacker, forward.
A magician's assistant who pretends to be a member of the audience.
One who knowingly allows himself or herself to be used for another's profit; a dupe.
A confederate; a person who is secretly working for the researcher, unknown to the study participant.
A straight man.
A secret informant for police.
To act as a straight man.