good vs just

good is a noun but just is not a noun.

Word	Noun	Adjective	Verb	Adverb
good	Yes	Yes	No	Yes
just	No	Yes	No	Yes

As adjectives, good and just are synonyms defined as:

Other synonyms of good include upright.

good (noun)	just (noun)
a raw material that is sold in large quantities, usually to other businesses for manufacturing or production purposes
benefit
moral excellence or admirableness
that which is pleasing or valuable or useful

good (adjective)	just (adjective)
having desirable or positive qualities especially those suitable for a thing specified	used especially of what is legally or ethically right or proper or fitting
morally admirable	fair to all parties as dictated by reason and conscience
promoting or enhancing well-being	free from favoritism or self-interest or bias or deception; conforming with established standards or rules
having the normally expected amount	of moral excellence
with or in a close or intimate relationship
thorough
generally admired
resulting favorably
not left to spoil
not forged
tending to promote physical well-being; beneficial to health
in excellent physical condition
appealing to the mind
agreeable or pleasing
exerting force or influence
most suitable or right for a particular purpose
capable of pleasing
deserving of esteem and respect
of moral excellence
having or showing knowledge and skill and aptitude
financially safe

good (adverb)	just (adverb)
(often used as a combining form) in a good or proper or satisfactory manner or to a high standard (`good' is a nonstandard dialectal variant for `well')	and nothing more
completely and absolutely (`good' is sometimes used informally for `thoroughly')	only a moment ago
	(used for emphasis) absolutely
	only a very short time before
	indicating exactness or preciseness
	exactly at this moment or the moment described
	possibly (indicating a slight chance of something being true)
	by a little