The Collaborative International Dictionary of English v.0.48:

Prayerless \Prayer"less\ (?; 277), a.
   Not using prayer; habitually neglecting prayer to God;
   without prayer. "The next time you go prayerless to bed."
   --Baxter.
   [1913 Webster] -- Prayer"less*ly, adv. --
   Prayer"less*ness, n.
   [1913 Webster]