Definition of unprecedented:
inventive, incomparable, unfamiliar, uncommon, unique, prodigious, modern, eccentric, single, curious, unexampled, odd, strange, preternatural, rare, untoward, scarce, aberrant, original, infrequent, abnormal, precious, idiosyncratic, unparalleled, new, innovative, newfangled, different, out-of-the-way, fresh, freakish, singular, anomalous, newfangled, bizarre, original.
Philoxene knocked at the door of the sumptuous room, and entering found her mistress with her eyes full of tears,- so unprecedented a phenomenon in the fifteen years she had waited upon her that the woman stopped short stupefied.- "Modeste Mignon", Honore de Balzac.
- "Openings in the Old Trail", Bret Harte.
- "The Emigrant Trail", Geraldine Bonner.