IPA: /ɪkˈstrimɪst/
KK: /ɪkˈstrimɪst/
The highest degree of something, indicating that it is more intense or severe than anything else.
The extremest weather conditions can be dangerous for travelers.
Comparative: more extreme
Superlative: most extreme
Extremest is formed from "extreme" (from Latin "extremus", meaning outermost or farthest) and the suffix "-est" (used to form the superlative degree). The word "extremest" refers to the highest degree of being extreme or the outermost limit.
Think of 'extreme' as meaning the 'outermost' or 'farthest' point, and remember that adding '-est' indicates the highest degree, making 'extremest' the most extreme.
No commonly confused words.