淹没 

Pinyin: yānmò 
Meaning：Submerge; flush; flood
Sentence：我的心已淹没在恐怖之中。My mind was submerged in terror.

More: 

淹： 

Pinyin: yān
Meaning: Submerge; drown; flood
Radical: 氵
Stokes: 11
Traditional: 淹
Common words/Phrase:
淹灌 [yānguàn] 【flush irrigation】
淹死 [yānsǐ] 【drown】

没： 

Pinyin: mò,méi
Meaning: not; be without
Radical: 氵
Stokes: 7
Traditional: 没
Common words/Phrase:
没收 [mòshōu] 【confiscate】