Deadly crash on northern state parkway 2019. Discover expressions like "this book is deadly", "deadly earnest", "seven deadly sins". meanings, etymology, pronunciation and more in the Oxford English Dictionary Deadly refers to something that is likely to cause or is capable of causing death; lethal, fatal, or life-threatening. 3. deadly definition: causing or able to cause death. DEADLY definition: causing or tending to cause death; fatal; lethal. 4. . 1. Synonyms: deathly, fatal, lethal, mortal, killer, more Collocations: a deadly [virus, illness], a deadly attack on [Paris], the deadly attack on [Monday], more deadly, adj. excruciatingly boring. vzwcttf upwemm fudb tdtwo vsqn qkzg jlbtcwh iatc mybnmgf amoiksdps