Incorrect spelling


Incorrect spelling, explanation: this is an incorrect form, because the word farewell comes from Middle English farwel and means, among others, wishes of good fortune. It is a mash-up of words fare and well, so spelling fairwell doesn’t make sense. The correct form is farewell.

Correct spelling


Correct spelling, explanation: the correct form is farewell since it is a combination of two words: fare (as in good fortune) and well. In Middle English, it was farwel, which spelling also points to the form farewell. Fairwell is a wrong form, probably mistaken due to pronunciation (which may be misleading to ESL learners).

Definition of farewell:
noun, wishes of good luck; departure
We threw him an amazing farewell party before his departure.