[massatoosits]

A “lecturer” to be precise... some scholar he...

[Octar]

A part-time guest lecturer to be even more precise. He lectured about Alinsky activism, according to those who attended his sessions.

[Tainan]

Technical name for his position was "adjunct lecturer."
A sort of call-in lecturer. Usually used for their knowledge in certain aspects of the course work that the regular instructor/professor either does not have (they will rarely admit this) or they want some time off from their class work. Not even considered part-time employee.

Can be a good deal for the adjunct person and the regular teacher.