1. concerned with work or important matters rather than play or trivialities
- a serious student of history
- a serious attempt to learn to ski
- gave me a serious look
2. of great consequence
- marriage is a serious matter
Similar word(s): important
3. causing fear or anxiety by threatening great harm
- a serious wound
- a serious turn of events
4. appealing to the mind
- a serious book
5. completely lacking in playfulness
6. requiring effort or concentration; complex and not easy to answer or solve
- raised serious objections to the proposal
- the plan has a serious flaw
Sentences with serious as an adjective:
- It was a surprise to see the captain, who had always seemed so serious, laugh so heartily.
- This is a serious problem. We'll need our best experts.
- After all these years, we're finally getting serious attention.