From BiblePortal Wikipedia

King James Dictionary [1]

Fa'Irly, adv.

1. Beautifully handsomely. Little used. 2. Commodiously conveniently as a town fairly situated for foreign trade. 3. Frankly honestly justly equitably without disguise, fraud or prevarication. The question was fairly stated and argued. Let us deal fairly with all men. 4. Openly ingenuously plainly. Let us deal fairly with ourselves or our own hearts. 5. Candidly.

I interpret fairly your design.

6. Without perversion or violence as, an inference may be fairly deduced from the premises. 7. Without blots in plain letters plainly legibly as an instrument or record fairly written. 8. Completely without deficience. His antagonist fought till he was fairly defeated. 9. Softly gently.

Webster's Dictionary [2]

(1): ( adv.) Softly; quietly; gently.

(2): ( adv.) Favorably; auspiciously; commodiously; as, a town fairly situated for foreign traade.

(3): ( adv.) In a fair manner; clearly; openly; plainly; fully; distinctly; frankly.

(4): ( adv.) Honestly; properly.