Incorrect spelling, explanation: this form is incorrect, although it is a common mistake, as the word professor comes directly from Latin, in which it is spelled exactly the same. Therefore proffesor is the wrong form: the correct one is professor – one f, double s.

Correct spelling, explanation: professor is a Latin word, and the spelling is exactly the same in English. Therefore it is perfectly clear that proffesor is a misspelling. The only correct form is professor.

Definition of professor:
noun, a teacher at a university of the highest academic degree
The extra lecture with professor Adams is postponed to April 15th due to health reasons.
My grandad used to be a professor at Oxford.

Incorrect spelling

Incorrect spelling