Unfair, v. t. — Webster enters it under “unfair”
Etymology: [1st pref. un- + fair.]
To deprive of fairness or beauty. [R.] Shak.
1 other Webster entry under this spelling
Unfair, a.
Not fair; not honest; not impartial; disingenuous; using or involving trick or artifice; dishonest; unjust; unequal. You come, like an unfair merchant, to charge me with being in your debt. Swift. -- Un*fair"ly, adv -- Un*fair"ness, n.
Shades of meaning
Fernald has no entry of its own for unfairness; he lists it under injustice, prejudice.
He lists it without comment; the entries above explain its neighbors.