seriousness

UK: ˈsɪəriəsnəs | US: ˈsɪriəsnəs

Definition
  1. n. the quality or state of being serious; earnestness or solemnity

  2. n. the quality of being important or significant

Structure
serious <grave, earnest>ness <noun suffix indicating state or quality>
Etymology

The word "seriousness" derives from the adjective "serious," which entered English in the early 15th century from Old French serieux (grave, earnest), itself from Latin serius (weighty, important). The suffix "-ness," of Old English origin, is used to form abstract nouns denoting a state or quality. Thus, "seriousness" literally means "the state of being serious," reflecting a transition from physical weight (Latin serius) to metaphorical gravity or importance in English.

Examples
  1. The seriousness of the situation demanded immediate action.

  2. Her seriousness about her studies impressed her teachers.

  3. He spoke with such seriousness that everyone listened intently.

  4. The doctor’s face showed the seriousness of the diagnosis.

  5. They underestimated the seriousness of the environmental crisis.