life style vs lifestyle

life style and lifestyle both are nouns.

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

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

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

Other synonyms of life style include life-style, modus vivendi.

life style (noun)	lifestyle (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