WordWeb Online

1. Having the physical appearance of death
   "a deathly pallor";
   - deathlike
    
2. Causing or capable of causing death
   - deadly, mortal

1. To a degree resembling death
   "he was deathly pale"
    
2. To an extreme degree
   "the night was deathly cold"; "as a child, I was deathly afraid of snakes";
   - extremely, exceedingly, super, stone

Derived forms: deathlier, deathliest

See also: dead, fatal, killing

Encyclopedia: Deathly