tutor

ot noun

1. One who teaches another (usually called a student, learner, or tutee) in a one-on-one or small-group interaction. He passed the difficult class with help from his tutor.
2. A university officer responsible for students in a particular hall.
3. One who has the charge of a child or pupil and his estate; a guardian.
4. (trading card games) A card that allows you to search your deck for one or more other cards.

fe’l verb

1. To instruct or teach, especially an individual or small group. To help pay her tuition, the college student began to tutor high school students in calculus and physics.
2. To treat with authority or sternness.