self-knowledge vs discernment

self-knowledge and discernment both are nouns.

Word	Noun	Adjective	Verb	Adverb
self-knowledge	Yes	No	No	No
discernment	Yes	No	No	No

As nouns, discernment is a hypernym of self-knowledge; that is, discernment is a word with a broader meaning than self-knowledge:

Other hypernyms of self-knowledge include apprehension, savvy, understanding.

self-knowledge (noun)	discernment (noun)
an understanding of yourself and your goals and abilities	the trait of judging wisely and objectively
	the mental ability to understand and discriminate between relations
	the cognitive condition of someone who understands
	perception of that which is obscure
	delicate discrimination (especially of esthetic values)