monitress

1. (now rare) A female mentor or advisor; a female observer.Examples: "Diana filled up all his heart: he felt as if by his union with her he had received a new and better soul. She was his monitress as he learned what were the true ends of life."; "Maisie could feel his monitress stiffen almost with anguish against the increase of his spell and then hurl herself as a desperate defence from it into the quite confessed poorness of violence, of iteration."archaic

2. (dated) A female monitor, or school leader.Examples: "Miss Mitchell would certainly be most relieved to have a monitress who was capable of organising the juniors at games."dated