The Collaborative International Dictionary of English v.0.48:

Slabber \Slab"ber\, n.
   Spittle; saliva; slaver.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Slabber \Slab"ber\, n. [See 1st Slab.] (Mach.)
   (a) A saw for cutting slabs from logs.
   (b) A slabbing machine.
       [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Slabber \Slab"ber\, v. i. [imp. & p. p. Slabbered; p. pr. &
   vb. n. Slabbering.] [OE. slaberen; akin to LG. & D.
   slabbern, G. schlabbern, LG. & D. slabben, G. schlabben,
   Icel. slafra. Cf. Slaver, Slobber, Slubber.]
   To let saliva or some liquid fall from the mouth carelessly,
   like a child or an idiot; to drivel; to drool. [Written also
   slaver, and slobber.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Slabber \Slab"ber\, v. t.
   1. To wet and foul spittle, or as if with spittle.
      [1913 Webster]

            He slabbered me over, from cheek to cheek, with his
            great tongue.                         --Arbuthnot.
      [1913 Webster]

   2. To spill liquid upon; to smear carelessly; to spill, as
      liquid foed or drink, in careless eating or drinking.
      [1913 Webster]

            The milk pan and cream pot so slabbered and tost
            That butter is wanting and cheese is half lost.
                                                  --Tusser.
      [1913 Webster]

WordNet (r) 3.0 (2006):

slabber
    v 1: let saliva drivel from the mouth; "The baby drooled" [syn:
         drivel, drool, slabber, slaver, slobber,
         dribble]

Moby Thesaurus II by Grady Ward, 1.0:

20 Moby Thesaurus words for "slabber":
   dribble, drivel, drool, expectorate, expectoration, foam, froth,
   hawk, mouth-watering, ptyalism, saliva, salivate, salivation,
   sialagogue, slaver, slobber, spew, spit, spittle, sputum