IPA: /ˈpiːsfəlɪst/
KK: /ˈpisfəlɪst/
The state of being the most calm and free from disturbance or conflict.
In the quiet garden, the atmosphere felt like the peacefulest place on earth.
Comparative: more peaceful
Superlative: peacefullest
Peacefullest → It is formed from "peace" (from Old French *pais*, meaning tranquility or absence of conflict) and "-ful" (meaning full of) and "-est" (a superlative suffix indicating the highest degree). The word "peacefullest" means the state of being most full of peace or tranquility.
Think of 'peace' as a state of tranquility, and remember that 'peacefullest' describes the highest degree of being full of peace.
No commonly confused words.