vital

adjective9

1. •
   Relating to or characteristic of life.

   • But open converse is there none, ⁠So much the vital spirits sink ⁠To see the vacant chair, and think, ‘How good! how kind! and he is gone.’ — 1850
2. •
   so important that something cannot work or go well without it

   • It is vital that you don't forget to do your homework.
3. •
   Necessary to continued existence.

   • The transition to farming was vital for the creation of civilisation.
4. •
   Necessary to the continuation of life; being the seat of life; being that on which life depends.

   • The brain is a vital organ.
5. •
   Relating to the recording of life events.

   • Birth, marriage and death certificates are vital records.
6. •
   Lively, having vitality

   • Montreal is a charming vital city with a large lesbian and gay population which clusters around a neighborhood not far from the center of town. — 1984
7. •
   Invigorating or life-giving.
8. •
   Capable of living; in a state to live; viable.

   • Pythagoras and Hippocrates […] affirming the birth of the seventh month to be vital. — 1650
9. •
   Containing life; living.

   • I ought to go upright and vital, and speak the rude truth in all ways. — 1841