un·der·age 
/ˌʌndɚˈeɪʤ/ adjective
/ˌʌndɚˈeɪʤ/ adjective : too young to do something legally
▪ They were not allowed into the club because they were underage. ▪ underage drinking ▪ an underage driver — opposite overage
▪ They were not allowed into the club because they were underage. ▪ underage drinking ▪ an underage driver — opposite overage
