Wordnet 3.0
ADJECTIVE (2)
1. 
 no longer in existence; 
 lost or especially having died out leaving no living representatives; 
- Example: "an extinct species of fish"- Example: "an extinct royal family"- Example: "extinct laws and customs"[syn: extinct, nonextant]
2.  no longer existing or inaccessible through loss or destruction; 
- Example: "its nonextant original was written on vellum"- G.B.Saul
The Collaborative International Dictionary of English v.0.48:
nonextant \nonextant\ adj.
   No longer existing; inaccessible through loss or destruction.
   [WordNet 1.5]
         Its nonextant original was written on vellum --G. B.
                                                  Saul
WordNet (r) 3.0 (2006):
nonextant
    adj 1: 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" [syn: extinct, nonextant] [ant:
           extant]
    2: no longer existing or inaccessible through loss or
       destruction; "its nonextant original was written on vellum"-
       G.B.Saul