Home › Words › D › deadlinessdeadliness/ˈdɛdlɪnəs/deadliness means synonym of lethality.; The quality of being deadly.deadliness is pronounced /ˈdɛdlɪnəs/.EtymologyFrom Middle English dedlinesse, deadlicnesse, from Old English dēadlīcnes, equivalent to deadly + -ness.nounSynonym of lethality.; The quality of being deadly.Synonym of lethality.; The degree to which a thing is deadly.Tedium, or the quality of being boring.Definitions & examples from Wiktionary (CC BY-SA 3.0).Words closest in meaningBy meaning, not spelling — each word's AI semantic fingerprint, nearest first.lethalness 84% match — The state or quality of being lethal; lethality. vs deadliness →lethality 81% match — The fact of something being lethal; the ability of something to kill. vs deadliness →deathliness 81% match — The state or quality of being deathly. vs deadliness →lethally 69% match — In a lethal manner, in manner which is or will be fatal. vs deadliness →deadlihood 69% match — The state of being dead; death. vs deadliness →fatally 67% match — In a deadly manner; lethally. vs deadliness →deadlike 66% match — Synonym of deathlike. vs deadliness →deathiness 66% match — The state or quality of being deathy. vs deadliness →