1demanding or characterized by careful consideration or application:marriage is a serious matterwe give serious consideration to safety recommendations
solemn or thoughtful in character or manner:her face grew serious
(of music, literature, or other art forms) requiring or meriting deep reflection:he bridges the gap between serious and popular music
2acting or speaking sincerely and in earnest, rather than in a joking or half-hearted manner:actors who are serious about their work
3significant or worrying because of possible danger or risk; not slight or negligible:she escaped serious injury
4 [attributive] informal substantial in terms of size, number, or quality:he suddenly had serious money to spend
