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.
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.