IPA: /ˈkwɪkɪst/
KK: /ˈkwɪkɪst/
The fastest in speed or time; the one that takes the least amount of time to do something.
She is the quickest runner in her class.
Quickest → It is formed from "quick" (from Old English "cwic", meaning alive or living) and the superlative suffix "-est" (meaning most). The word "quickest" means the most alive or the fastest in terms of speed or response.
Think of 'alive' ('cwic') to remember that 'quickest' refers to being the most alive or the fastest.
No commonly confused words.