concern vs interest

concern and interest both are nouns.

Word	Noun	Adjective	Verb	Adverb
concern	Yes	No	Yes	No
interest	Yes	No	Yes	No

As nouns, interest is a hypernym of concern; that is, interest is a word with a broader meaning than concern:

concern: something that interests you because it is important or affects you
interest: a sense of concern with and curiosity about someone or something

Other hypernyms of concern include involvement.

As verbs, interest is a hyponym of concern; that is, interest is a word with a more specific, narrower meaning than concern:

As verbs, concern and interest are synonyms defined as:

Other synonyms of concern include occupy, worry.

concern (noun)	interest (noun)
something that interests you because it is important or affects you	a diversion that occupies one's time and thoughts (usually pleasantly)
something or someone that causes anxiety; a source of unhappiness	a reason for wanting something done
a feeling of sympathy for someone or something	the power of attracting or holding one's attention (because it is unusual or exciting etc.)
an anxious feeling	a sense of concern with and curiosity about someone or something
a commercial or industrial enterprise and the people who constitute it	(usually plural) a social group whose members control some field of activity and who have common aims
	a fixed charge for borrowing money; usually a percentage of the amount borrowed
	(law) a right or legal share of something; a financial involvement with something

concern (verb)	interest (verb)
be relevant to	excite the curiosity of; engage the interest of
be on the mind of	be of importance or consequence
	be on the mind of