Sat vs weekday

Sat and weekday both are nouns.

Word	Noun	Adjective	Verb	Adverb
Sat	Yes	No	No	No
weekday	Yes	No	No	No

As nouns, weekday is a hypernym of Sat; that is, weekday is a word with a broader meaning than Sat:

Sat: the seventh and last day of the week; observed as the Sabbath by Jews and some Christians
weekday: any day except Sunday (and sometimes except Saturday)

Sat (noun)	weekday (noun)
the seventh and last day of the week; observed as the Sabbath by Jews and some Christians	any day except Sunday (and sometimes except Saturday)