IPA: /ˈstɪl.ɪst/
KK: /ˈstɪlɪst/
The quietest or most calm; having no movement or sound.
The stillest night allowed us to hear the faintest sounds of nature.
Comparative: stiller
Superlative: stillest
Stillest → It is formed from "still" (from Old English *stille*, meaning quiet or motionless) and the superlative suffix "-est" (meaning most). The word "stillest" means the most quiet or motionless.
Think of 'still' meaning quiet or motionless, and remember that 'stillest' refers to the most quiet or motionless state.