submerge in WordNet English dictionary

1. fill or cover completely, usually with water
   inundate  deluge  submerge 
   
2. cover completely or make imperceptible
   "I was drowned in work"; "The noise drowned out her speech"
   submerge  drown  overwhelm 
   
3. put under water
   "submerge your head completely"
   submerge  submerse 
   
4. sink below the surface; go under or as if under water
   submerge  submerse