Mistake
Error
If you're confused and you make a mistake, no matter how much you didn't mean it, it's still a mistake. You should ask for help next time you don't know what you're doing and you won't make these errors.
さくご
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
ちょっとそれは時代錯誤じゃないか。
Don’t you think that’s a little anachronistic?