Grum \Grum\, a. [Cf. Dan. grum furious, Sw. grym, AS. gram, and E. grim, and grumble. [root]35.] 1. Morose; severe of countenance; sour; surly; glum; grim. ``Nick looked sour and grum.'' --Arbuthnof. 2. Low; deep in the throat; guttural; rumbling; as,