relinquishing vs ending

relinquishing and ending both are nouns.

Word	Noun	Adjective	Verb	Adverb
relinquishing	Yes	No	No	No
ending	Yes	No	No	No

As nouns, ending is a hypernym of relinquishing; that is, ending is a word with a broader meaning than relinquishing:

Other hypernyms of relinquishing include conclusion, termination.

relinquishing (noun)	ending (noun)
the act of giving up and abandoning a struggle or task etc.	the act of ending something
a verbal act of renouncing a claim or right or position etc.	the end of a word (a suffix or inflectional ending or final morpheme)
	the last section of a communication
	event whose occurrence ends something
	the point in time at which something ends