a noun is a word that functions as the name of a person, place, thing, or idea. In this capacity, 'life' functions as a word to refer to the period of existence of a living creature or organism.
rules and use cases for 'life' as a noun include the following
when referring to living things, 'life' is almost always an uncountable noun (i.e., it cannot be used with numbers, and its plural form is not used).
1. Hoards of starfish have returned to the beach, signaling the arrival of new life.
2. We may consider a life of luxury to be the ultimate success.
3. Life can be filled with painful memories, yet joyous moments as well.
see the uncountable noun rule noted above—'life' should generally not be used in its plural form (for example, do not say 'lives') and should not be paired with numbers.
when 'life' is used in an adjectival capacity, it typically describes something related to or associated with life or living.
He has a life-changing opportunity to study abroad.
The documentary provided a life-affirming message about human resilience.
They went on a life-saving mission to rescue the stranded climbers.
When 'life' is used as part of a compound adjective before a noun, it's typically hyphenated, as in 'life-sized' or 'life-threatening.' Be cautious not to confuse these compound adjectives with noun phrases. For instance, 'life changing event' (noun phrase) vs. 'life-changing event' (compound adjective).