teacher someone who teaches as their job, especially in a school : a high school teacher
tutor someone who gives private lessons to one student or a small group of students. In Britain, a tutor is also a teacher in a university : They hired a tutor to help him with his English. | Your tutor will help you find a subject for your essay. lecturer someone who teaches in a university or college : University lecturers aren’t very well paid.
professor a teacher in a college or university. In Britain, a professor is a high-ranking university teacher, especially one who is head of a department : She was professor of linguistics at Cambridge University.
instructor someone who teaches a sport or a practical skill such as swimming or driving : He works as a ski instructor in the winter. | a driving instructor
coach someone who helps a person or team improve in a sport : a professional tennis coach
trainer someone who teaches people particular skills, especially the skills they need to do a job : a teacher trainer | Many companies pay outside trainers to teach management skills to their staff.