teach (one's) grandmother to suck eggs

To try to teach an older person who is wiser and more experienced and wordly than a young person may think. Why are you explaining basic typing to Ethel? Yes, she's 70, but she's been using a computer since before you were born—quit teaching your grandmother to suck eggs.

Common Names:

Name	Pronounced	Usage
Herb	HURB	English
Roshanara	-	Persian (Archaic)
Cadmus	-	Greek Mythology (Latinized)
Lowery	['ləuəri]
Makarios	-	Late Greek
Mumina	-	Arabic