RhymeZone: undeadly definitions

Definitions of undeadly:

adjective: Not subject to death; immortal.
adjective: Unable to be killed, quenched, or terminated; eternal; everlasting.
adjective: Of or pertaining to the undead.
adverb: Immortally; eternally.
adjective: Not deadly; not causing, producing, or resulting in death; harmless.

(Definitions from Wiktionary)