Un*prob"a*bly (?), adv. [Pref. un- not + probably.]
Improbably.
© Webster 1913.
Un*prob"a*bly, adv. [Un- + L. probabilis approvable, fr. probare to approve. Cf. Probable.]
In a manner not to be approved of; improperly.
[Obs. & R.]
To diminish, by the authority of wise and knowing men, things unjustly and unprobably crept in.
Strype.
© Webster 1913.