1. 死一般地
If you say that someone is deathly pale or deathly still, you are emphasizing that they are very pale or still, like a dead person.

2. 极其;非常
If you say that someone is deathly afraid, you are emphasizing that they are very afraid. You can also say that someone or something is deathly silent, dull, boring, cold, or tired.

3. （沉默或寂静）死一般的
If you say that there is a deathly silence or a deathly hush, you are emphasizing that it is very quiet.

1. having the physical appearance of death

e.g. a deathly pallor

Synonym: deathlike

2. causing or capable of causing death

e.g. a fatal accident
a deadly enemy
mortal combat
a mortal illness

Synonym: deadlymortal