arena vs responsibility

arena and responsibility both are nouns.

Word	Noun	Adjective	Verb	Adverb
arena	Yes	No	No	No
responsibility	Yes	No	No	No

As nouns, responsibility is a hyponym of arena; that is, responsibility is a word with a more specific, narrower meaning than arena:

Other hyponyms of arena include distaff, front, kingdom, land, realm, lap, political arena, political sphere, preserve, province.

arena (noun)	responsibility (noun)
a playing field where sports events take place	the social force that binds you to the courses of action demanded by that force
a large structure for open-air sports or entertainments	a form of trustworthiness; the trait of being answerable to someone for something or being responsible for one's conduct
the central area of an ancient Roman amphitheater where contests and spectacles were held; especially an area that was strewn with sand	the proper sphere or extent of your activities
a particular environment or walk of life