radical chic vs mannerism

radical chic and mannerism both are nouns.

Word	Noun	Adjective	Verb	Adverb
radical chic	Yes	No	No	No
mannerism	Yes	No	No	No

As nouns, mannerism is a hypernym of radical chic; that is, mannerism is a word with a broader meaning than radical chic:

radical chic: an affectation of radical left-wing views and the fashionable dress and lifestyle that goes with them
mannerism: a deliberate pretense or exaggerated display

Other hypernyms of radical chic include affectation, affectedness, pose.

radical chic (noun)	mannerism (noun)
an affectation of radical left-wing views and the fashionable dress and lifestyle that goes with them	a deliberate pretense or exaggerated display
	a behavioral attribute that is distinctive and peculiar to an individual