Formal:
* Interred: This is a more formal synonym for "entombed," usually referring to the burial of a body.
* Buried: This is the most common synonym for "entombed."
* Inhumed: This is another formal synonym for "buried" or "interred."
* Sequestered: This implies a sense of isolation or confinement.
Informal:
* Trapped: This suggests a situation where someone or something is unable to escape.
* Confined: This implies a sense of limitation or restriction.
* Sealed: This suggests a situation where something is completely enclosed.
* Locked away: This suggests something is hidden or inaccessible.
Figurative:
* Engulfed: This suggests something is completely surrounded or overwhelmed.
* Swallowed: This suggests something is completely consumed or absorbed.
* Submerged: This suggests something is completely covered or hidden.
* Frozen: This suggests a state of stillness or inactivity.
The best word to use will depend on the specific situation and the tone you want to convey.