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.]
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The Collaborative International Dictionary of English v.0.48:

Slobber \Slob"ber\, v. t. & i.
   See Slabber.
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The Collaborative International Dictionary of English v.0.48:

Slobber \Slob"ber\, n.
   1. See Slabber.
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   2. (Zool.) A jellyfish. [Prov. Eng.]
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   3. pl. (Vet.) Salivation.
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WordNet (r) 3.0 (2006):

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