/ ˈdedli; NAmE / adjective , adverb
■ adjective ( dead·lier , dead·li·est )
HELP NOTE : More deadly and deadliest are the usual forms. You can also use most deadly .
1.
causing or likely to cause death
SYN lethal :
a deadly weapon / disease
deadly poison
The cobra is one of the world's deadliest snakes.
The terrorists have chosen to play a deadly game with the civilian population.
2.
[ only before noun ] extreme; complete :
I'm in deadly earnest .
We sat in deadly silence .
They are deadly enemies (= are full of hatred for each other) .
3.
extremely effective, so that no defence is possible :
His aim is deadly (= so accurate that he can kill easily) .
It was the deadly striker's 11th goal of the season.
4.
( informal ) very boring :
The lecture was absolutely deadly.
■ adverb
1.
( informal ) extremely :
deadly serious / dull
2.
= deathly :
deadly pale / cold
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WORD ORIGIN
Old English dēadlīc mortal, in danger of death (see dead , -ly ).