life-style vs fast lane

life-style and fast lane both are nouns.

Word	Noun	Adjective	Verb	Adverb
life-style	Yes	No	No	No
fast lane	Yes	No	No	No

As nouns, fast lane is a hyponym of life-style; that is, fast lane is a word with a more specific, narrower meaning than life-style:

life-style: a manner of living that reflects the person's values and attitudes
fast lane: a hectic and pressured lifestyle often characterized by recklessness or dissipation

Other hyponyms of life-style include free living, vanity fair, nomadism, settledness.

life-style (noun)	fast lane (noun)
a manner of living that reflects the person's values and attitudes	the traffic lane for vehicles that are moving rapidly
	a hectic and pressured lifestyle often characterized by recklessness or dissipation