serious

/ˈsɪriəs/
adjective
  1. Not joking or laughing; showing a sincere and thoughtful attitude.
    • She had a serious expression on her face during the meeting.
    • Please be serious for a moment; this is important.
    • He gave a serious answer to my question.
  2. Important and needing careful thought or attention.
    • The doctor said the injury was serious but not life-threatening.
    • We need to have a serious conversation about our budget.
    • Climate change is a serious problem for the whole world.
  3. Large in amount, degree, or effect; significant.
    • She has a serious amount of homework this weekend.
    • The storm caused serious damage to the coastal town.
    • There has been a serious increase in the cost of living.
  4. Sincere and genuine about something; not pretending.
    • I'm serious when I say we should leave now.
    • Are you serious about learning to play the guitar?
    • He is a serious candidate for the job.