And the english word "adult" is from the latin perfect passive participle "adultus", which means "grown up".
As long as you don't use "adulto" instead (as I've done several times). :D
Watch out for the word 'adulta' which means adulterous, which is not at all what it sounds like.
As I read the sentence I saw the word "kulo", which is very similar to spanish "culo", that means ass, and I started laughing out loud. I guess I know now which one of these I am.
As a Spanish speaker, I made the same mental association. The word 'plenkreskulo' does sound funny to us!
I'm surprised "mal" isn't used in this pair. Either adolto /maladolto or infano / malinfano
I'm not sure I'd consider adult and child opposites. Is kitten the opposite of cat?
On a side note, now I'm wondering if homido would fly.
"homido" would literally mean "a human being's offspring", regardless of age. So it isn't really the same as "infano".
I've never heard that either, but I think it should be preferred in a natural science class, when talking about species.
Is a child the opposite of an adult? I don't think so. Is a kitten the opposite of a cat?
Not really (assuming that by "infant" you mean "young child"). "Infano" just means "child".