IPA: /ˈɡrɪzliər/
KK: /ˈgrɪzliər/
More gruesome or horrifying than something else; often used to describe something that causes fear or disgust.
The movie was grislier than the last one, with more shocking scenes.
Comparative: grislier
Superlative: grisliest
Grislier is formed from "grisly" (from Old English "grislic", meaning fearful or horrible) and the comparative suffix "-er" (meaning more). The word "grislier" means more grisly or more fearful in nature.
Think of something that is 'more fearful' or 'more horrible' — that's what grislier means.