adj. grim·mer, grim·mest
1. Unrelenting; rigid.
2. Uninviting or unnerving in aspect; forbidding: “undoubtedly the grimmest part of him was his iron claw” (J.M. Barrie).
3. Ghastly; sinister: “He made a grim jest at the horrifying nature of his wound” (Reginald Pound). See Synonyms at ghastly.
4. Dismal; gloomy: a grim, rainy day.
5. Ferocious; savage: the grim advance of the pillaging army.
Have you ever been in a location where everything is so very dull around you? Grey concrete and rusty metal surrounds you.