adj.
- demanding or characterized by careful consideration or application.
▸solemn or thoughtful.
- sincere and in earnest, rather than joking or half-hearted.
- significant or worrying in terms of danger or risk:
serious injury.
- informal substantial in terms of size, number, or quality:
serious money.
Derivative
Etymology
ME: from OFr. serieux or late L. seriosus, from L. serius ‘earnest, serious’.