life style vs manner

life style and manner both are nouns.

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

As nouns, manner is a hypernym of life style; that is, manner is a word with a broader meaning than life style:

life style: a manner of living that reflects the person's values and attitudes
manner: how something is done or how it happens

Other hypernyms of life style include fashion, mode, style, way.

life style (noun)	manner (noun)
a manner of living that reflects the person's values and attitudes	a way of acting or behaving
	how something is done or how it happens
	a kind