1. [adj]  no longer existing or inaccessible through loss or destruction; "its nonextant original was written on vellum"- G.B.Saul
2. [adj]  no longer in existence; lost or especially having died out leaving no living representatives; "an extinct species of fish"; "an extinct royal family"; "extinct laws and customs"

NONEXTANT is a 9 letter word that starts with N.