We don't have synonyms for fair wind yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are tail wind, fall wind and air wing.
°(nautical) A wind blowing in the direction the sailor wants to go, ie. favourably. (Reference: Ray Parkin, H. M. Bark Endeavour, Miegunyah Press, second edition 2003, ISBN 0-522-85093-6, page 210.).
°(nautical) A wind blowing in the direction the sailor wants to go, ie. favourably. (Reference: Ray Parkin, H. M. Bark Endeavour, Miegunyah Press, second edition 2003, ISBN 0-522-85093-6, page 210.).