Fast vs Hasty vs Rapid

When to use each in English, with meaning, register, and examples.

Fast

Top 1,000 (very common)A1adjective

Hasty

Top 5,000 (fairly common)B1adjective

Rapid

Top 2,000 (common)B2adjective
Most common: Fast
 FastHastyRapid
Pronunciation🇬🇧 /["/fɑːst/"]/🇺🇸 /["/fæst/"]/🇬🇧 //ˈheɪ sti//🇺🇸 //ˈheɪsti//🇬🇧 //ˈræp.ɪd//🇺🇸 //ˈræp.ɪd//
MeaningMoving or happening quickly.Doing things quickly without thinking carefully.happening very quickly
ExampleShe runs very fast when she is late for school.His hasty decision led to unexpected consequences.The rapid changes in technology are hard to keep up with.
RegisterNeutralNeutralNeutral
How commonTop 1,000 (very common)Top 5,000 (fairly common)Top 2,000 (common)
CEFR levelA1B1B2
Part of speechadjectiveadjectiveadjective
Collocationsbe, seem, extremely, fairly, very, be, seem, extremely, fairly, veryhasty decision, hasty retreat, hasty judgmentrapid response, rapid increase, rapid change
Antonymsslowslow, careful, deliberateslow, gradual, leisurely
Common mistakes'Fast' is sometimes confused with 'quick' improperly., Learners often forget that 'fast' can be used for both time and physical speed., Some may incorrectly add 'ly' to make it an adverb (fastly).Confusing 'hasty' with 'hasty decision', thinking it applies only to choices., Using 'hasty' as a noun or verb instead of an adjective., Forgetting that 'hasty' implies negative connotations.Confusing with 'quick', which implies speed but may not denote the same urgency., Using 'rapid' in contexts where a slower pace is typical.
Usage notesUse 'fast' to describe speed, but be cautious when using it with 'to' (as in 'to fast', it means to not eat for a period of time). Appropriate in both written and spoken contexts.Use 'hasty' to describe actions taken too quickly, often leading to mistakes. It's suitable for both formal and informal contexts. Avoid using it in overly casual conversations.Used to describe actions or changes that occur with speed. Suitable for both formal and informal contexts.

Frequently asked questions: Fast vs Hasty vs Rapid

What's the difference between Fast, Hasty, and Rapid?

Fast: Moving or happening quickly. Hasty: Doing things quickly without thinking carefully. Rapid: happening very quickly

Which is more common: Fast, Hasty, and Rapid?

Fast is the most common in everyday English.

Which is more advanced: Fast, Hasty, and Rapid?

Rapid is the highest level, at B2, on the CEFR scale.

Are Fast, Hasty, and Rapid the same CEFR level?

Fast: A1, Hasty: B1, Rapid: B2 on the CEFR scale.

What part of speech are Fast, Hasty, and Rapid?

Fast: adjective, Hasty: adjective, Rapid: adjective.

Can you show an example of each?

Fast: She runs very fast when she is late for school. Hasty: His hasty decision led to unexpected consequences. Rapid: The rapid changes in technology are hard to keep up with.

Can I use Fast, Hasty, and Rapid interchangeably?

Not always. Fast, Hasty, and Rapid are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.

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