What is the meaning of the word "grave"?

Definitions:

a place for the burial of a corpse,especially beneath the ground and marked by a tombstone noun
- They put flowers on their mother's grave.
carve, cut, or etch into a material or surface verb
- engrave a pen
causing fear or anxiety by threatening great harm adjective
- The doctor's expression turned grave as he delivered the news about the patient's condition.
death of a person noun
- They went to their grave unexpectedly.
dignified and somber in manner or character and committed to keeping promises adjective
- a grave Godfearing man
of great gravity or crucial import adjective
- Understanding the crucial import of this provision is essential to fully appreciating the scope of the agreement.