suffix vs ending

suffix and ending both are nouns.

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

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

suffix: an affix that is added at the end of the word
ending: the end of a word (a suffix or inflectional ending or final morpheme)

Other hypernyms of suffix include affix, termination.

suffix (noun)	ending (noun)
an affix that is added at the end of the word	the act of ending something
	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

suffix (verb)	ending (verb)
attach a suffix to