adjective
also un·dreamt “+
Etymology: un- (I) + dreamed, dreamt, past participle of dream
: not dreamed : not thought of : unimagined — usually used with of
undreamed -of capacity for cooperation with their fellows — J.H.Robinson †1936
impersonal forces have been set in motion on a scale undreamed of in the early days of the republic — John Dewey
the printing press was probably undreamed of a half century before its invention