vital in WordNet English dictionary

1. urgently needed; absolutely necessary
   "a critical element of the plan"; "critical medical supplies"; "vital for a healthy society"; "of vital interest"
   critical  vital 
   
2. full of spirit
   "a dynamic full of life woman"; "a vital and charismatic leader"; "this whole lively world"
   full of life  lively  vital 
   
3. performing an essential function in the living body
   "vital organs"; "blood and other vital fluids"; "the loss of vital heat in shock"; "a vital spot"; "life-giving love and praise"
   vital  life-sustaining 
   
4. manifesting or characteristic of life
   "a vital, living organism"; "vital signs"
   vital