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?