good vs summum bonum

good and summum bonum both are nouns.

Word	Noun	Adjective	Verb	Adverb
good	Yes	Yes	No	Yes
summum bonum	Yes	No	No	No

As nouns, summum bonum is a hyponym of good; that is, summum bonum is a word with a more specific, narrower meaning than good:

good: moral excellence or admirableness
summum bonum: the supreme good in which all moral values are included or from which they are derived

good (noun)	summum bonum (noun)
a raw material that is sold in large quantities, usually to other businesses for manufacturing or production purposes	the supreme good in which all moral values are included or from which they are derived
benefit
moral excellence or admirableness
that which is pleasing or valuable or useful

good (adjective)	summum bonum (adjective)
having desirable or positive qualities especially those suitable for a thing specified
morally admirable
promoting or enhancing well-being
having the normally expected amount
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)	summum bonum (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')
completely and absolutely (`good' is sometimes used informally for `thoroughly')