曜日 is "day of the week"
If you say 今日は何曜日?, you mean "is it Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, or Sunday?"
週日 is "weekday," as in "days of the week that are not the weekend" (however whether only Sunday is excluded or both Saturday and Sunday are excluded may depend on context).
I don't personally hear it very often. 平日 is the more common word to express that idea.
Yeah I don't think you need to know the word 週日 for any level of JLPT. I can't recall any situation where someone used it.
Well, thanks to you two!
I was quite hopeless about anyone actually replying, and y'all helped me, so...
Thanks and have a good day!
N5 student here!
Hi, I'm Allen
I study for N5 and this doubt came across my mind
How is 曜日 different from 週日?
Aren't they both the same word? Weekday?
Thx
xx
Allen