an “equivocator” is a person who speaks ambiguously or doesn’t tell the whole truth.

An example can be:

Just after he has been named Thane of Cawdor, Macbeth is wondering if he can believe the rest of the witches’ prophecies, and Banquo remarks, “oftentimes, to win us to our harm, / The instruments of darkness tell us truths, / Win us with honest trifles, to betray’s / In deepest consequence” . Banquo is warning Macbeth that the witches could lure him to great evil by telling small truths. Even though Banquo doesn’t use the word “equivocation,” it’s what he’s talking about.