Vital

1. n. A vital part; one of the vitals.
2. a. Belonging or relating to life, either animal or vegetable; as, vital energies; vital functions; vital actions.
3. a. Contributing to life; necessary to, or supporting, life; as, vital blood.
4. a. Containing life; living.
5. a. Being the seat of life; being that on which life depends; mortal.
6. a. Very necessary; highly important; essential.
7. a. Capable of living; in a state to live; viable.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.