speedy
Used to describe something that happens or moves quickly, often implying efficiency and promptness. Commonly used in informal situations.
- The repair service was very speedy; they fixed my car in just an hour.
- Order a pizza from them if you want a speedy delivery.
fast
General term for something that moves quickly or happens in a short amount of time. Suitable for both formal and informal situations.
- She is a fast runner and wins every race.
- The internet connection in our office is really fast.
rapid
Often used in more formal or technical contexts to describe something that happens quickly, especially when it involves a series of quick changes.
- The rapid growth of the tech industry is remarkable.
- We need a rapid response to this emergency.
swift
Used to describe something that happens quickly and smoothly, often with an undertone of elegance. Slightly more formal.
- The bird made a swift dive towards the water.
- He took swift action to prevent the crisis.