Serious Definition & Meaning - Adjective

American

British

Related Words

Other Word Forms

Etymology

Examples

Related Words

Synonyms serious American [seer-ee-uhs] / ˈsɪər i əs /

adjective

1. of, showing, or characterized by deep thought.

2. of grave or somber disposition, character, or manner.

   a serious occasion; a serious man.

   Synonyms: staid, sedate, sober

3. being in earnest; sincere; not trifling.

   His interest was serious.

   Antonyms: trifling, frivolous

4. requiring thought, concentration, or application.

   serious reading; a serious task.

5. weighty or important.

   a serious book; Marriage is a serious matter.

   Synonyms: grave, momentous Antonyms: trivial

6. giving cause for apprehension; critical.

   The plan has one serious flaw.

7. Medicine/Medical. (of a patient's condition) having unstable or otherwise abnormal vital signs and other unfavorable indicators, as loss of appetite and poor mobility: patient is acutely ill.

noun

1. that which is of importance, grave, critical, or somber.

   You have to learn to separate the serious from the frivolous.

serious British / ˈsɪərɪəs /

adjective

1. grave in nature or disposition; thoughtful

   a serious person

2. marked by deep feeling; in earnest; sincere

   is he serious or joking?

3. concerned with important matters

   a serious conversation

4. requiring effort or concentration

   a serious book

5. giving rise to fear or anxiety; critical

   a serious illness

6. informal worthy of regard because of substantial quantity or quality

   serious money

   serious wine

7. informal extreme or remarkable

   a serious haircut

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Related Words

See earnest 1.

Other Word Forms

• half-serious adjective
• half-seriously adverb
• nonserious adjective
• nonseriously adverb
• overserious adjective
• overseriously adverb
• quasi-serious adjective
• quasi-seriously adverb
• seriousness noun
• superserious adjective
• superseriously adverb
• ultraserious adjective
• ultraseriously adverb
• unserious adjective
• unseriously adverb

Etymology

Origin of serious

First recorded in 1400–50; late Middle English, from Middle French serieux and Latin sērius “grave, earnest” or Late Latin sēriōsus; -ous, -ose 1

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Both sides present it as a serious clash of principles, but it’s a distraction from the real problem of AI misalignment.

From The Wall Street Journal

I staggered toward the wall and put my bag up there, but then wasn’t quite tall enough to sit without some serious scrambling.

From Literature

Finally it was over, the lights went on for good, and Treebaun turned to us, his lined face serious as he took the time to look each of us in the eye.

From Literature

Lady Drummond told him: "It will be obvious to you that these are very serious offences which have caused harm and upset to Kimberley's grieving family."

From BBC

Second is serious damage to the region’s oil production or infrastructure, especially the kind that would disrupt spare capacity in Saudi Arabia and the United Arab Emirates.

From The Wall Street Journal

Related Words

• dangerous
• deep
• difficult
• far-reaching
• grievous
• important
• major
• meaningful
• severe
• significant
• tough
• urgent

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.