seriousness Definition

serious
adj

1. Grave or solemn; not inclined to flippancy or lightness of mood.

Thesaurus: earnest, sincere, sober, solemn, grave, deliberate, thoughtful; Antonym: facetious, smiling.
2. Dealing with important issues.

Example: a serious newspaper
3. Severe.

Example: a serious accident
Thesaurus: dangerous, acute, critical, alarming, grim; Antonym: slight, trivial.
4. Important; significant.

Example: There were serious differences of opinion
Thesaurus: momentous, urgent, critical, weighty, complex; Antonym: slight, trivial.
5. Showing firmness of intention; sincere or earnest.

Example: I am serious about doing it
6. colloq
Notable, renowned or in significant quantities.
Example: That is a serious set of wheels
Example: serious money

Derivative: seriously
adverb

Derivative: seriousness
noun

Etymology: 15c: from Latin seriosus, from serius.