in·fan·tile 
/ˈɪnfənˌtajəl/ adjective
/ˈɪnfənˌtajəl/ adjective 1 [more infantile; most infantile] disapproving : annoying and childish : very silly in a way that is not appropriate or polite
▪ His behavior was infantile. ▪ infantile jokes 2 always used before a noun, medical : affecting babies or very young children
▪ infantile diseases
▪ His behavior was infantile. ▪ infantile jokes
▪ infantile diseases
