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crucial

/ˈkruː.ʃəl/
IELTSAcademic
adjective

Extremely important in a way that affects the result of something. A crucial thing is not just important — it is the key factor that decides success or failure.

  • Regular sleep is crucial for good health and concentration.
  • The coach made a crucial decision in the final minutes.
  • Strong vocabulary is crucial for scoring well in IELTS.

Adinary Nuance

Crucial sits in a group with critical, vital, essential, and important — but they are not freely interchangeable. Important is the weakest: it means something matters, but carries no urgency. Crucial implies a turning point — the outcome genuinely depends on this one factor. Critical overlaps closely but also carries a sense of crisis or danger (e.g., "critical condition"), making it feel more alarming. Vital suggests life-or-death necessity and sounds more emotional or dramatic. Essential means something is a required ingredient — you simply cannot do without it. In academic and IELTS writing, crucial is the best choice when you want to stress that one specific factor decides everything; use essential when you mean something is a baseline requirement.

In other languages

Vietnamese
Cực kỳ quan trọng
Spanish
Crucial
Chinese
至关重要的
Japanese
非常に重要な
Korean
결정적인

Etymology

From Latin "crux" (cross, or decisive point), entering English via French in the early 18th century. The original sense referred to a cross-shaped test or a critical trial — a moment where two paths meet and a choice must be made.

Common phrases

play a crucial roleat a crucial momentcrucial to successa crucial decision

Synonyms

Related words

Frequently asked questions

Is 'crucial' stronger than 'important'?
Yes. 'Important' simply means something matters a lot. 'Crucial' is stronger — it means the result depends specifically on this one thing. Use 'crucial' when you want to show that a factor is truly decisive.
What is the difference between 'crucial' and 'critical'?
Both mean extremely important, but 'critical' can also describe a dangerous or emergency situation (e.g., 'the patient is in a critical condition'). 'Crucial' stays focused on the idea of a turning point or decisive factor, without the medical or crisis connotation.
Can I use 'crucial' in IELTS academic writing?
Yes, 'crucial' is well-suited for IELTS essays and academic reports. It signals a high level of vocabulary and is appropriate in formal written English. Avoid repeating 'important' — swap in 'crucial', 'vital', or 'essential' to show range.
How do I use 'crucial' correctly in a sentence?
'Crucial' is usually followed by 'to' + noun/gerund, or 'that' + clause. For example: 'Exercise is crucial to good health.' or 'It is crucial that you submit the form before the deadline.'