Fast vs Speedy

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

Fast

Top 1,000 (very common)A1adjective

Speedy

Top 3,000 (common)
Most common: Fast
 FastSpeedy
Pronunciation🇬🇧 /["/fɑːst/"]/🇺🇸 /["/fæst/"]/🇬🇧 //ˈspiːdi//🇺🇸 //ˈspiːdi//
MeaningMoving or happening quickly.moving or happening quickly
ExampleShe runs very fast when she is late for school.The delivery service is known for its speedy arrival times.
RegisterNeutralNeutral
How commonTop 1,000 (very common)Top 3,000 (common)
CEFR levelA1-
Part of speechadjective
Collocationsbe, seem, extremely, fairly, very, be, seem, extremely, fairly, veryspeedy delivery, speedy recovery, speedy service, speedy response
Antonymsslowslow, sluggish, lethargic
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 'speedy' with 'fast' which are often interchangeable but 'speedy' can imply efficiency., Using 'speedy' for slow processes, which is incorrect., Forget to pair 'speedy' with a noun, leading to incomplete expressions.
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 'speedy' in contexts where quickness is praised. It's appropriate in both spoken and written English, but more common in informal settings.

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Fast
Speedy

Frequently asked questions: Fast vs Speedy

What's the difference between Fast and Speedy?

Fast: Moving or happening quickly. Speedy: moving or happening quickly

Which is more common: Fast and Speedy?

Fast is the most common in everyday English.

Can you show an example of each?

Fast: She runs very fast when she is late for school. Speedy: The delivery service is known for its speedy arrival times.

Can I use Fast and Speedy interchangeably?

Not always. Fast and Speedy 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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