Main Entry: ¹dead·ly

Pronunciation: \ˈded-lē\

Function: adjective

Inflected Form(s): dead·li·er; dead·li·est

Date: before 12th century

1 : likely to cause or capable of producing death <deadly poison>
2 a : aiming to kill or destroy : implacable <a deadly enemy> b : highly effective <a deadly exposé> c : unerring <a deadly marksman> d : marked by determination or extreme seriousness
3 a : tending to deprive of force or vitality <a deadly habit> b : suggestive of death especially in dullness or lack of animation <deadly bores> <a deadly conversation>
4 : very great : extreme

— dead·li·ness noun

synonyms deadly, mortal, fatal, lethal mean causing or capable of causing death. deadly applies to an established or very likely cause of death <a deadly disease>. mortal implies that death has occurred or is inevitable <a mortal wound>. fatal stresses the inevitability of what has in fact resulted in death or destruction <fatal consequences>. lethal applies to something that is bound to cause death or exists for the destruction of life <lethal gas>.