crucially

crucially — adverb

1. To an extremely important degree that decides a final result.

1.adverbB2
Definition

To an extremely important degree that decides a final result.

Example

Marta's research was crucially important for developing the new vaccine.

collocation: crucially important

The rescue team crucially needed more time to locate the missing hikers before nightfall.

adverb before main verb for urgency

Common collocations
  • crucially important
  • crucially different
  • crucially depend on
  • crucially needed
Synonyms
  • vitally

    very close in meaning; 'vitally important' and 'crucially important' are interchangeable

  • critically

    emphasises a make-or-break point, often in medical or technical contexts

  • essentially

    focuses on the core nature of something rather than its decisive impact

  • fundamentally

    suggests the very basis or foundation of something is at stake

Antonyms
  • marginally

    suggests only a small, unimportant difference

  • slightly

    indicates a tiny degree of importance or change

Grammar Patterns

crucially + adjective

crucially + verb

Crucially, + clause

Usage Note

Commonly used before adjectives (especially 'important' and 'different') and verbs that express need, influence, or dependence. As a sentence adverb at the start of a clause, it signals that the following statement is the decisive factor in the argument.

Common Mistakes

This is crucially for the project.
This is crucially important for the project.
'crucially' must modify an adjective or verb; it does not pair directly with a noun phrase.
Crucially, it is a good plan.' (vague).
Crucially, the plan includes a backup for every risk.
after 'crucially,' give a specific reason why something matters, not a general opinion.

Word family

  • crucial
    adjectiveB2
  • crucialness
    nounC2

Synonym discussion

Sense: adverb/1

All four words express a high degree of importance, but they focus on different aspects. 'Vitally' is the closest synonym to 'crucially' — both are used before 'important' and suggest something is essential for life or success. 'Critically' goes a step further, implying that failure at this point would be disastrous or unrecoverable; it is common in medicine ('critically ill') and engineering ('critical failure'). 'Essentially' highlights the core identity or nature of something ('essentially the same method'), whereas 'fundamentally' points to the underlying basis or foundation ('fundamentally flawed design'). Choose 'crucially' or 'vitally' when something is extremely important but not necessarily life-or-death; use 'critically' when the situation is at a breaking point. For example: 'Funding is crucially important for the project.' vs. 'The patient's condition is critically unstable.'

vitally ↗critically ↗essentially ↗fundamentally ↗

Common collocations

Phrases

  • crucially important
  • crucially different
  • crucially depend on
  • crucially needed

Etymology

LatinFrenchEnglish

Formed in English by adding the adverbial suffix '-ly' to 'crucial', which comes from French 'crucial' and directly from Latin 'crux' (meaning 'cross'). The Latin root refers to a crossroads or a turning point where a decision determines the path ahead — hence the modern sense of decisive importance.