life style vs life-style

life style and life-style both are nouns.

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

As nouns, life style and life-style are synonyms defined as:

life style and life-style: a manner of living that reflects the person's values and attitudes

Other synonyms of life style include lifestyle, modus vivendi.

life style (noun)	life-style (noun)
a manner of living that reflects the person's values and attitudes	a manner of living that reflects the person's values and attitudes