selection vs willing

selection and willing both are nouns.

Word	Noun	Adjective	Verb	Adverb
selection	Yes	No	No	No
willing	Yes	Yes	No	No

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

selection (noun)	willing (noun)
the act of choosing or selecting	the act of making a choice
the person or thing chosen or selected
a passage selected from a larger work
an assortment of things from which a choice can be made
a natural process resulting in the evolution of organisms best adapted to the environment

selection (adjective)	willing (adjective)
	disposed or inclined toward
	not brought about by coercion or force