deathly /ˈdɛθli/adjective 3adverb 2forms 4 adjective3 •Appearing as though dead, or on the verge of death.He has a deathly pallor. •Extreme.He has a deathly fear of crocodiles. •Deadly, fatal, causing death. adverb2 •In a way that resembles death.He was deathly pale. •Extremely, dreadfully.The water was deathly cold.He was deathly afraid of crocodiles. formsdeathlier · more deathly · deathliest · most deathly