'Improbably' definitions:

Definition of 'improbably'

(from WordNet)
adverb
Not easy to believe; "behind you the coastal hills plunge to the incredibly blue sea backed by the Turkish mountains" [syn: incredibly, improbably, implausibly, unbelievably] [ant: believably, credibly, plausibly, probably]

Definition of 'Improbably'

From: GCIDE
  • Improbable \Im*prob"a*ble\, a. [L. improbabilis; pref. im- not + probabilis probable: cf. F. improbable. See Probable.] Not probable; unlikely to be true; not to be expected under the circumstances or in the usual course of events; as, an improbable story or event. [1913 Webster]
  • He . . . sent to Elutherius, then bishop of Rome, an improbable letter, as some of the contents discover. --Milton. -- {Im*prob"a*ble*ness}, n. -- {Im*prob"a*bly}, adv. [1913 Webster]