Word To Use Today: nonage.

 Whereas a nonagenarian is a person who has reached the age of at least ninety, nonage describes someone who is legally too young to do something like marrying, or driving a car, or entering into a contract.

You say the word NOHnidge.

I don't know if the difference between the two meanings is annoying, or just completely charming.

But then a lot of things are like that.

Word To Use Today: nonage. The non- in nonagenarian comes from the Latin nōnāginta, which means ninety. The non- in nonage comes from the Latin nōn, which means not. Nonage came to English from the Old French nonaage. Age comes from the Latin aevum, which means age, but also lifetime or an eternity or just a long time, as in Dark Ages.