adjective se·ri·ous \ ˈsir-ē-əs \
|Updated on: 21 Aug 2018

Definition of serious

1 : thoughtful or subdued in appearance or manner : sober
  • a quiet, serious girl
2 a : requiring much thought or work
  • serious study
b : of or relating to a matter of importance
  • a serious play
3 a : not joking or trifling : being in earnest
  • a serious question
b archaic : pious
c : deeply interested : devoted
  • a serious musician
4 a : not easily answered or solved
  • serious objections
b : having important or dangerous possible consequences
  • a serious injury
5 : excessive or impressive in quality, quantity, extent, or degree
  • serious stereo equipment
  • making serious money
  • serious drinking



Examples of serious in a Sentence

  1. “You sound terrible.” “It's just a bad cold. Nothing serious.”

  2. For my brother, not going to college was a serious mistake.

  3. Crime is a serious problem in this neighborhood.

  4. The team is a serious contender for the championship.

  5. If you want to quit smoking, you have to make a serious effort.

  6. They had a serious conversation about their relationship.

  7. a serious novel about modern life

  8. The story raises serious questions about our system of justice.

  9. Dog shows are a serious business.

  10. She is a serious cyclist who rides 200 miles each week.

Recent Examples of serious from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'serious.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of serious

Middle English seryows, from Anglo-French or Late Latin; Anglo-French serious, from Late Latin seriosus, alteration of Latin serius weighty, serious; probably akin to Old English swǣr heavy, sad

Synonym Discussion of serious

serious, grave, solemn, sedate, staid, sober, earnest mean not light or frivolous. serious implies a concern for what really matters.
    • a serious play about social injustice
grave implies both seriousness and dignity in expression or attitude.
    • read the proclamation in a grave voice
solemn suggests an impressive gravity utterly free from levity.
    • a sad and solemn occasion
sedate implies a composed and decorous seriousness.
    • remained sedate amid the commotion
staid suggests a settled, accustomed sedateness and prim self-restraint.
    • a quiet and staid community
sober stresses seriousness of purpose and absence of levity or frivolity.
    • a sober look at the state of our schools
earnest suggests sincerity or often zealousness of purpose.
    • an earnest reformer

SERIOUS Defined for English Language Learners


Definition of serious for English Language Learners

  • : having an important or dangerous possible result

  • : involving or deserving a lot of thought, attention, or work

  • : giving a lot of attention or energy to something

SERIOUS Defined for Kids


adjective se·ri·ous \ ˈsir-ē-əs \

Definition of serious for Students

1 : not joking or funny
  • a serious drama
2 : being such as to cause distress or harm
  • a serious accident
3 : thoughtful or quiet in appearance or manner
  • a serious person
4 : requiring much thought or work
  • a serious task



Synonym Discussion of serious

serious, solemn, and earnest mean not funny or not playful. serious means being concerned or seeming to be concerned about really important things.
    • He's a serious student.
solemn is used for dignity along with complete seriousness.
    • The preacher is always very solemn.
earnest means that someone is sincere and has serious intentions.
    • She's an earnest, diligent student.

Medical Dictionary


adjective se·ri·ous \ ˈsir-ē-əs \

medical Definition of serious

: having important or dangerous possible consequences
  • a serious injury

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