Definify.com

Webster 1913 Edition

Adj.

Destitute of an heir.

Shak.

Adj.

areless. Destitute of an heir.

heirless ‎(not comparable)

Without an heir.
- 2009 August 2, Dan Bilefsky, “Hurdles in Eastern Europe Thwart Restitution Claims”, in New York Times:
  A number of Western European countries, led by Germany, carried out far-reaching measures to provide restitution of Nazi-looted properties in the aftermath of World War II, including setting up commissions to deal with heirless property and communal property illegally seized during the war.

without heirs