IPA: /ˈɡruːsəmɪst/
KK: /ˈgruːsəmɪst/
The most shocking or horrifying, often related to something that causes fear or disgust.
The movie was known for its gruesomest scenes that left the audience in shock.
Comparative: more gruesome
Superlative: gruesomest
Gruesomest is formed from "gruesome" (from Middle English "gruesom", meaning causing horror or disgust) and the superlative suffix "-est" (meaning most). The word "gruesomest" means the most horrifying or disgusting.
Think of something that causes the most horror or disgust — that's what gruesomest means.