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