what's the difference between “juvenile” and “childish”

Question

According to the merriam-webster dictionary:

Definition of juvenile

1 : physiologically immature or undeveloped : young juvenile birds

2 a : of, relating to, characteristic of, or suitable for children or young people juvenile fiction b : of or relating to young people who have committed or are accused of committing a criminal offense the juvenile justice system juvenile crime

3 : reflecting psychological or intellectual immaturity : childish juvenile behavior juvenile pranks told him he was being juvenile

4 : derived from sources within the earth and coming to the surface for the first time —used especially of water and gas

I am wondering what's the difference between he was being juvenile and he was being childish?

Answer 1

When talking about people, a juvenile isn't a child, a child is younger than a juvenile. For example some youth detention centres (prisons) are called juvenile detention centres, they don't lock up children.

On the other hand when used as an adjective "childish" is very close to "juvenile" because both can be used to simply mean immature. Both juveniles and children are immature.

As another example, an infant is younger than a child, but the word "infantile" is very similar to both "childish" and "juvenile" as adjectives to mean immature, naive or unwise.

In your question what is the difference between he was being juvenile and he was being childish?, I'd have to say not much. They both express that he was behaving immaturely or inappropriately according to the expected norm or standards.