seriousness

seriousness — noun

1. how bad, harmful, or dangerous a problem, illness, or difficult situation is — f

1.nounB2
Definition

how bad, harmful, or dangerous a problem, illness, or difficult situation is — for example, the seriousness of a disease, a crime, or an economic downturn.

Example

The doctor told Yuki's family about the seriousness of her grandmother's heart problem.

collocation: the seriousness of [a medical condition]

It was only after the flood that people understood the seriousness of the damage.

pattern: 'it was…that' structure showing delayed awareness

Common collocations
  • the seriousness of the situation
  • the seriousness of the problem
  • the seriousness of the injury
  • the seriousness of the issue
  • the seriousness of the crime
  • the seriousness of the matter
Synonyms
  • gravity

    slightly more formal; preferred for political, legal, or moral contexts ('gravity of the offence')

  • severity

    nearly identical in meaning; often used for physical intensity ('severity of the injury')

  • magnitude

    focuses on scale or size rather than danger or harm ('magnitude of the disaster')

Antonyms
  • triviality

    the quality of being unimportant or minor

Grammar Patterns

the seriousness of [something]

Usage Note

Uncountable noun. Almost always used with the definite article ('the seriousness of...'). The subject is typically a problem, illness, injury, mistake, or dangerous situation. Common in both formal and everyday contexts.

Common Mistakes

I did not understand the serious of the situation.
I did not understand the seriousness of the situation.
'serious' is an adjective; use the noun 'seriousness' after the article 'the'.
He spoke about the problem with seriously.
He spoke about the problem with seriousness.
Use the noun, not the adverb, after the preposition 'with'.

2. the quality of being sincere and meaning what you say or do, rather than joking

2.nounB2
Definition

the quality of being sincere and meaning what you say or do, rather than joking or being playful — for example, speaking with seriousness about a difficult topic, or treating a task with seriousness.

Example

Zayd spoke with such seriousness that everyone in the room stopped laughing.

pattern: 'with such + noun + that-clause' showing result

The seriousness of the young lawyer's voice made the jury pay close attention.

Common collocations
  • with great seriousness
  • in all seriousness
  • the seriousness of purpose
  • the seriousness of his tone
  • the seriousness of the occasion
Synonyms
  • sincerity

    emphasises honesty and genuine feeling rather than absence of humour

  • earnestness

    very close in meaning; slightly old-fashioned but interchangeable

  • solemnity

    more formal; often used for ceremonies, rituals, or formal occasions

Antonyms
  • frivolity

    lack of seriousness; light-hearted or playful attitude

Grammar Patterns

with (great) seriousness

in all seriousness

Usage Note

Uncountable noun. Often describes a person's tone, manner, attitude, or the atmosphere of an event. Distinguish from sense 1 (SEVERITY), which describes how bad something is rather than how sincere someone is. 'In all seriousness' is a common fixed phrase used to mark a shift from joking to earnest speech.

Common Mistakes

She treated the topic with serious.
She treated the topic with seriousness.
After the preposition 'with', use the noun form, not the adjective.
I say this in all seriously.
I say this in all seriousness.
The fixed phrase 'in all seriousness' uses the noun, not the adverb 'seriously'.
Idioms

in all seriousness

idiom

used to show that you are not joking and genuinely mean what you are about to say, especially when shifting from a light-hearted topic to a more serious one

In all seriousness, we need to find a new place to live before the rent goes up again.

In all seriousness, thank you for driving three hours just to help me move.

Word family

Synonym discussion

Sense: noun/1

Gravity, severity, and magnitude all relate to how serious something is, but they highlight different aspects. Gravity (B2) suggests deep, wide-reaching consequences and is more common in formal or official contexts ('the gravity of the political crisis'). Severity (B2) is the closest synonym to seriousness and can often be used interchangeably, though it tends to emphasise physical intensity ('the severity of the storm') rather than abstract importance. Magnitude (B2) focuses on size, scale, or scope rather than danger or harm ('the magnitude of the task ahead'). A doctor might discuss the seriousness or severity of a condition, but not its magnitude; an engineer might discuss the magnitude of a construction project but not its gravity.

gravity ↗severitymagnitude ↗

Common collocations

Phrases

Prepositions

Etymology

LatinFrenchEnglish

The noun 'seriousness' is formed from the adjective 'serious' (from Old French 'serieux', from Latin 'serius' meaning 'grave, earnest') plus the native English suffix '-ness', which turns adjectives into nouns meaning 'the state or quality of'. The Latin root 'serius' is of uncertain origin but may be related to an Indo-European root meaning 'heavy' or 'weighty'. In English, both the 'not joking' sense and the 'severe' sense were well established by the 1500s.