Source : Webster's Revised Unabridged Dictionary (1913)

Grub \Grub\, v. i. [imp. & p. p. {Grubbed}, p. pr. & vb. n.
   {Grubbing}.] [OE. grubbin., cf. E. grab, grope.]
   1. To dig in or under the ground, generally for an object
      that is difficult to reach or extricate; to be occupied in
      digging.

   2. To drudge; to do menial work. --Richardson.

Grub \Grub\, v. t.
   1. To dig; to dig up by the roots; to root out by digging; --
      followed by up; as, to grub up trees, rushes, or sedge.

            They do not attempt to grub up the root of sin.
                                                  --Hare.

   2. To supply with food. [Slang] --Dickens.

Grub \Grub\, n.
   1. (Zo["o]l.) The larva of an insect, especially of a beetle;
      -- called also grubworm. See Illust. of {Goldsmith
      beetle}, under {Goldsmith}.

            Yet your butterfly was a grub.        --Shak.

   2. A short, thick man; a dwarf. [Obs.] --Carew.

   3. Victuals; food. [Slang] --Halliwell.

   {Grub ax} or {axe}, a kind of mattock used in grubbing up
      roots, etc.

   {Grub breaker}. Same as {Grub hook} (below).

   {Grub hoe}, a heavy hoe for grubbing.

   {Grub hook}, a plowlike implement for uprooting stumps,
      breaking roots, etc.

   {Grub saw}, a handsaw used for sawing marble.

   {Grub Street}, a street in London (now called {Milton
      Street}), described by Dr. Johnson as ``much inhabited by
      writers of small histories, dictionaries, and temporary
      poems, whence any mean production is called grubstreet.''
      As an adjective, suitable to, or resembling the production
      of, Grub Street.

            I 'd sooner ballads write, and grubstreet lays.
                                                  --Gap.

Source : WordNet®

grub
     v 1: ask for and get free; be a parasite [syn: {mooch}, {bum}, {cadge},
           {sponge}]
     2: search about busily
     [also: {grubbing}, {grubbed}]

grub
     n 1: informal terms for a meal [syn: {chow}, {chuck}, {eats}]
     2: a soft thick wormlike larva of certain beetles and other
        insects
     [also: {grubbing}, {grubbed}]