Entry 1 sense Webster, 1913 Grim /(grĭm)/ · IPA /ɡɹɪm/ 01 a. Of forbidding or fear-inspiring aspect; fierce; stern; surly; cruel; frightful; horrible. 1. Of forbidding or fear-inspiring aspect; fierce; stern; surly; cruel; frightful; horrible. “Whose grim aspect sets every joint a-shaking.” — Shak. “The ridges of grim war.” — Milton. Syn. Fierce; ferocious; furious; horrid; horrible; frightful; ghastly; grisly; hideous; stern; sullen; sour.