At basic level, students often have only 'fast' and 'slow' for speed. The car is fast. The bus is slow. But English has several words for different aspects of speed. 'Fast' is for high physical speed — moving at high velocity. 'Quick' is for taking little time — finishing soon, completing without delay. The two overlap a lot but emphasise different things. 'Rapid' is more formal — used in writing and reports for fast change or movement. 'Swift' is also formal — often suggests smooth, efficient speed. 'Slow' is the basic opposite of fast and quick. 'Sluggish' is a more emphatic word for slow — suggesting dull, low-energy slowness. Each fits different situations. Students who use only 'fast' and 'slow' miss the precision available. The grammar matters too. 'Fast' is both an adjective and an adverb (a fast car / drive fast). 'Quick' is mostly an adjective; the adverb is 'quickly'. This lesson covers the main speed words at B1 level.
Before you start — think honestly about your own teaching and experience.
Look at the examples. Answer each question before reading the explanation — this is how your students will learn too.
The car is fast — it goes 200 km per hour. (= high physical speed)
The meal was quick — only fifteen minutes from order to eating. (= took little time)
A fast runner can cover a long distance in a short time. (high physical speed)
A quick reply is a reply that comes soon. (takes little time)
For most situations, both words work:
The bus is fast / quick on this route. (both correct, slight emphasis difference)
When does the difference between fast and quick matter?
'Fast' emphasises high physical velocity — high speed in motion. A fast car, a fast runner, a fast plane. 'Quick' emphasises taking little time — short duration, completed soon. A quick lunch (eaten in a short time). A quick reply (sent soon). The two overlap when speed and duration both apply: 'a quick journey' could mean a short journey (quick = duration) or a fast journey (quick = velocity). For most everyday use, both words work and the difference is small. But for precision: use 'fast' for physical speed (cars, runners, planes); use 'quick' for time taken (replies, meals, decisions). 'A fast decision' is unusual; 'a quick decision' is natural — because decisions are about time, not motion.
rapid (= fast, formal):
The rapid growth of the city has caused traffic problems.
Rapid changes in technology challenge older workers.
swift (= fast and smooth, formal):
The swift response from the emergency team saved lives.
The ball moved with swift precision into the goal.
speedy (= fast, slightly less formal than rapid):
We wish you a speedy recovery from your illness.
When do students need formal speed words? When are they better than 'fast'?
Formal speed words appear often in writing — reports, news, academic articles, formal speech. 'Rapid' is the most common formal alternative to 'fast'. 'Rapid growth' (in economics or population) is more standard than 'fast growth'. 'Rapid change' (in technology, society) sounds more academic than 'fast change'. 'Swift' often suggests smooth efficiency along with speed — a swift response means quick AND skilled. 'Speedy' is slightly less formal but still more elevated than 'fast'. 'Speedy recovery' is a fixed wish for someone who is ill. Students writing essays or formal reports should reach for these words instead of 'fast' for a more sophisticated style. In casual conversation, 'fast' is fine. Match the word to the register.
The traffic was slow this morning. (= moving at low speed)
The progress has been slow but steady. (= not advancing quickly)
The lift is sluggish — it takes ages between floors. (= dull, low-energy slow)
The economy is sluggish. (= weak, slow growth)
What does 'sluggish' add that 'slow' does not?
'Slow' is the general word for not fast. 'Sluggish' adds something more — a sense of dullness, low energy, or lack of vitality. A sluggish lift moves slowly AND seems lazy or tired. A sluggish economy is slow AND lacking the energy to grow. A sluggish morning describes a slow start with no enthusiasm. 'Slow' is neutral; 'sluggish' is more negative and emphatic. The opposite of swift is sometimes 'sluggish' (smooth fast vs dull slow). Students who learn 'sluggish' have a more precise word for the kind of slowness that involves lack of energy. For neutral slow, use 'slow'. For dull, low-energy slow, use 'sluggish'.
| Word | Meaning | Register | Typical use |
|---|---|---|---|
| fast | High physical speed (velocity) | Neutral, any context | A fast car, a fast runner, drive fast (adjective and adverb). |
| quick | Taking little time | Neutral | A quick reply, a quick meal, a quick decision. Adverb: quickly. |
| rapid | Fast — formal, often for change | Formal | Rapid growth, rapid change, rapid increase. |
| swift | Fast and smooth, often skilled | Formal, literary | A swift response, swift action, a swift movement. |
| speedy | Fast — slightly less formal than rapid | Neutral to formal | A speedy recovery (fixed phrase), a speedy delivery. |
| hasty | Done too quickly without thinking | Neutral | A hasty decision, a hasty reply. Often slightly negative. |
| slow | Not fast, low speed | Neutral, any context | A slow car, slow progress. Adjective and adverb (drive slow / slowly). |
| sluggish | Slow with low energy or dull | Neutral | A sluggish economy, a sluggish lift, a sluggish start. |
DISTINCTION 1 — Fast vs quick: Fast is about velocity (physical speed). Quick is about duration (taking little time). A fast car has high speed. A quick reply takes little time. The two overlap (a quick journey is fast; a fast meal takes little time) but emphasise different things. For motion, fast is more natural; for duration, quick.
DISTINCTION 2 — Fast as both adjective and adverb: 'Fast' is unusual in that it works as both adjective (a fast car) and adverb (drive fast) without changing form. 'Quick' is mostly an adjective; the adverb is 'quickly'. Drive quickly (not 'drive quick' — which exists but is non-standard).
DISTINCTION 3 — Rapid vs fast: Both mean high speed. Rapid is more formal — common in academic and professional writing. Rapid change, rapid growth, rapid development are standard formal expressions. Fast change is everyday but less formal. For essays and reports, rapid is the safer choice.
DISTINCTION 4 — Swift adds smoothness: Swift means fast AND smooth, often suggesting skill or efficiency. A swift response is quick and well-handled. A swift movement is smooth as well as fast. Use swift when smooth efficiency is part of the meaning, not just speed.
DISTINCTION 5 — Sluggish for dull slowness: Slow is neutral. Sluggish adds dullness or low energy. A sluggish lift is slow AND seems tired or unresponsive. A sluggish economy is slow AND lacking vigour. The negative emotional weight of sluggish makes it useful when slow is too neutral.
DISTINCTION 6 — Hasty is too quick: Hasty means done too quickly without thinking. A hasty decision is one made without enough thought. A hasty reply might be regretted later. Hasty is slightly negative — quick in a careless way. Use it when the speed is a problem, not a virtue.
Speed adjectives come up constantly in everyday and formal contexts — describing cars, processes, change, growth, action. Students who know only 'fast' and 'slow' miss the precision available. The lesson connects to comparatives (#12) — speed words have comparative forms (faster, quicker, more rapid). It also connects to adverb formation (#42) — quickly, slowly, rapidly all follow the -ly rule. The grammar of 'fast' as adverb is unusual — students should know it can stand alone (drive fast) without -ly.
Use real examples of speed to teach the words. A car on a highway → fast. A reply to a message → quick. The growth of a city → rapid. A response from an emergency team → swift. A lift that takes ages → sluggish. A decision made without thinking → hasty. Real situations make the differences memorable.
Choose the best speed word for each context. Think about whether the speed is physical motion, time taken, or formal description.
Each sentence has a problem with a speed word. Suggest a better version and explain.
Use this sequence directly in class — guided discovery, no textbook needed. Tap each step to mark it done.
STEP 1 — Fast vs quick (5 min): Write 'a fast car' and 'a quick reply' on the board. Discuss the difference. Fast = physical velocity. Quick = taking little time. They overlap but emphasise different things. Drill five examples each.
STEP 2 — The adverb question (5 min): Show that 'fast' works as both adjective (a fast car) and adverb (drive fast — no -ly needed). 'Quick' is mostly adjective; the adverb is 'quickly'. Drill: 'drive fast' / 'drive quickly' — both correct. 'Drive quick' — non-standard.
STEP 3 — Formal speed words (7 min): Drill rapid, swift, speedy, hasty. Rapid is for formal change (rapid growth). Swift is for smooth efficient speed (swift response). Speedy is in fixed phrases (speedy recovery). Hasty is for too-quick-without-thinking (hasty decision). Match each to a context.
STEP 4 — The slow side (6 min): Drill slow and sluggish. Slow is general. Sluggish adds dullness or low energy. A sluggish lift is slow AND seems lazy. A sluggish economy is slow AND weak. Practise five examples of each.
STEP 5 — Match speed to situation (7 min): Give five situations: a sports car, a formal report on growth, an emergency response, a careless decision, a slow lift. Students choose the right word. Discuss as a class. The exercise drills matching word to context.
Use directly in class — copy, adapt, or read aloud. No printing needed.
For each strategy, choose the option that best describes where you are now.
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