unconcern vs feeling

unconcern and feeling both are nouns.

Word	Noun	Adjective	Verb	Adverb
unconcern	Yes	No	No	No
feeling	Yes	No	No	No

As nouns, feeling is a hypernym of unconcern; that is, feeling is a word with a broader meaning than unconcern:

unconcern (noun)	feeling (noun)
the trait of remaining calm and seeming not to care; a casual lack of concern	the experiencing of affective and emotional states
a feeling of lack of concern	an intuitive understanding of something
	a physical sensation that you experience
	the sensation produced by pressure receptors in the skin
	a vague idea in which some confidence is placed
	the general atmosphere of a place or situation and the effect that it has on people