Core word: Fast
Speedy
1
: moving or able to move quickly : fast or quick
a speedy car/boat
2
: happening quickly
a speedy process
They wished her a speedy recovery.
Swift
1
: happening or done quickly or immediately
a swift and accurate response
a swift kick
2
: moving or able to move very fast
a swift horse/runner 驰骋的骏马/飞人
a swift river current 湍急的河流
Rapid
1
: happening in a short amount of time : happening quickly
a rapid [=quick] change in temperature
There's been rapid growth in the number of new businesses in the town.
Scientists are concerned about the rapid disappearance of the island's coral reefs.岛屿上短时间内消失的珊瑚礁石
2
: having a fast rate 很快的频率
a rapid heartbeat 急速的心跳,高频率的心跳
rapid breathing 急促的呼吸
3
: moving quickly
She carefully guided the boat through the rapid water. 湍急的水流
Hasty
1
a : done or made very quickly
Seeing the dog, the cat made/beat a hasty retreat up a tree. 撤回到树上
b : done or made too quickly
We don't want to make any hasty decisions. 仓促的决定
a hasty marriage 闪婚
Fleet ( 文学范的表达~)
: very fast
a fleet runner
She is very fleet of foot. [=she is able to run very fast]