life-time vs afterlife

life-time and afterlife both are nouns.

Word	Noun	Adjective	Verb	Adverb
life-time	Yes	No	No	No
afterlife	Yes	No	No	No

As nouns, afterlife is a hyponym of life-time; that is, afterlife is a word with a more specific, narrower meaning than life-time:

life-time: the period during which something is functional (as between birth and death)
afterlife: life after death

Other hyponyms of life-time include hereafter.

life-time (noun)	afterlife (noun)
the period during which something is functional (as between birth and death)	life after death