[ ded-lee ]
/ ˈdɛd li /

adjective, dead·li·er, dead·li·est.


in a manner resembling or suggesting death: deadly pale.
excessively; completely: deadly dull.

Origin of deadly

before 900; Middle English deedli(ch), Old English dēadlīce. See dead, -ly


1 See fatal.
4 dull, tedious, tiresome.

Related forms

dead·li·ness, nounnon·dead·ly, adjective

Can be confused

deadly deathly Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for deadlier

British Dictionary definitions for deadlier


/ (ˈdɛdlɪ) /

adjective -lier or -liest

likely to cause deathdeadly poison; deadly combat
informal extremely boring

adverb, adjective

like death in appearance or certaintydeadly pale; a deadly sleep

Derived Forms

deadliness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012