underage /ˌʌndəɹˈeɪd͡ʒ/adjective 3/ˈʌndəɹɪd͡ʒ/ noun 1forms 1 adjective3 •Below the legal age (usually age 18 or 21) for some activity, such as consuming alcohol or engaging in sexual intercourse.The bar was fined for serving alcohol to an underage customer.He was arrested for driving while underage. •Not yet a legal adult; still a minor. •(Ireland) Limited to players below a certain age; junior.Even if an underage team is stacked with talent, there is still only one senior team they can graduate to and there are a finite amount of places. — 2025 underage /ˈʌndəɹɪd͡ʒ/ noun1 •A deficit or shortfall in funds, inventory, or capacity. formsunderages