Source : Webster's Revised Unabridged Dictionary (1913)

Grumble \Grum"ble\, v. i. [imp. & p. p. {Grunbled}; p. pr. & vb.
   n. {Grumbling}.] [Cf. LG. grummeln, grumman, D. grommelen,
   grommen, and F. grommeler, of German origin; cf. W. grwm,
   murmur, grumble, surly. [root]35. Cf. {Grum}, {Grim}.]
   1. To murmur or mutter with discontent; to make ill-natured
      complaints in a low voice and a surly manner.

            L'Avare, not using half his store, Still grumbles
            that he has no more.                  --Prior.

   2. To growl; to snarl in deep tones; as, a lion grumbling
      over his prey.

   3. To rumble; to make a low, harsh, and heavy sound; to
      mutter; as, the distant thunder grumbles.