enfeebling vs weakening

enfeebling is not a noun while weakening is a noun.

Word	Noun	Adjective	Verb	Adverb
enfeebling	No	Yes	No	No
weakening	Yes	Yes	No	No

As adjectives, enfeebling and weakening are synonyms defined as:

Other synonyms of enfeebling include debilitative, enervating.

enfeebling (noun)	weakening (noun)
	the act of reducing the strength of something
	becoming weaker

enfeebling (adjective)	weakening (adjective)
causing debilitation	causing debilitation
	moderating by making pain or sorrow weaker