IPA: /ˈɡrɪmɪli/
KK: /ˈɡrɪmɪli/
In a way that shows a serious or gloomy attitude.
She smiled grimily at the thought of the difficult task ahead.
Grimily is formed from "grim" (from Old English "grim", meaning fierce or cruel) and the suffix "-ly" (meaning in a manner of). The word "grimily" means in a fierce or cruel manner.
Think of someone acting in a 'fierce' way ('grim') — the '-ly' shows how they are doing it, so 'grimily' means doing something in a fierce manner.