Teacher

A teacher was an individual who was well versed in a subject and made money by teaching others, typically children or young adults. The Doctor has encountered numerous teachers in his travels. Two of the First Doctor's first companions were teachers. Ian Chesterton and Barbara Wright, who taught Susan, followed Susan to a junk yard when worried for her safety and quickly became caught up in the Doctor's travels. (TV: An Unearthly Child)

Clara Oswald became a teacher at Coal Hill School after the events on Trenzalore. (TV: Day of the Doctor)