serious, grave, solemn, sedate, staid, sober, earnest mean not light or frivolous. serious implies a concern for what really matters.

Please don't laugh - I'm being serious. He was wearing a very serious expression and I knew something was wrong. On the surface it's a very funny novel but it does have a more serious underlying theme.

Find 173 different ways to say SERIOUS, along with antonyms, related words, and example sentences at Thesaurus.com.

Any important situation is serious, and this word is also the opposite of humorous and playful.

SERIOUS definition: of, showing, or characterized by deep thought. See examples of serious used in a sentence.

If someone is serious about something, they are sincere about what they are saying, doing, or intending to do.

What Is The Difference Between “Serious” and “Seriously”? “Serious” is an adjective that modifies nouns. You might see it used in sentences like “you’re not serious,” where “you” is the noun to …

Definition of serious adjective in Oxford Advanced American Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

Feb 21, 2026 · Adjective serious (comparative more serious, superlative most serious) Without humor or expression of happiness; grave in manner or disposition.

Definition of serious. What does serious mean? Meaning of serious. serious synonyms, pronunciation, spelling and more from Free Dictionary.