- to find out definitely; learn with certainty or assurance; determine: to ascertain the facts.
- Archaic. to make certain, clear, or definitely known.
Origin of ascertain
Examples from the Web for unascertainable
There was first the Procession of the Maestranza, of unascertainable antiquity.Diversions in Sicily
H. Festing Jones
Antonyms: unknowable, unascertainable, incognoscible, unrecognizable.Putnam's Word Book
Louis A. Flemming
The composition of the earliest inks has not yet been obtained and, likely, is unascertainable.The Reign of the Manuscript
Perry Wayland Sinks
During the seventh century many sanguinary battles were fought, the sites of which are now unascertainable.On Some Ancient Battle-Fields in Lancashire
The exact date of his advent to that place seems to be unascertainable, but it was more than fifty years ago.The Old Pike
Thomas B. Searight
- to determine or discover definitely
- archaic to make certain
Word Origin and History for unascertainable
early 15c., "to inform, to give assurance," from Anglo-French acerteiner, Old French acertener "to assure, certify" (13c.), from a "to" (see ad-) + certain "certain" (see certain). Modern meaning of "find out for sure by experiment or investigation" is first attested 1794. Related: Ascertained; ascertaining.