undeadly vs unkillable

undeadly

adj
  • Unable to be killed, quenched, or terminated; eternal; everlasting. 

  • Of or pertaining to the undead. 

  • Not deadly; not causing, producing, or resulting in death; harmless. 

  • Not subject to death; immortal. 

adv
  • Immortally; eternally. 

unkillable

adj
  • Not killable; unable to be killed. 

How often have the words undeadly and unkillable occurred in a corpus of books? (source: Google Ngram Viewer )