The Collaborative International Dictionary of English v.0.48:

Slaver \Slav"er\, v. i. [imp. & p. p. Slavered; p. pr. & vb.
   n. Slavering.] [Cf. Icel. slafra. See Slabber.]
   1. To suffer spittle, etc., to run from the mouth.
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   2. To be besmeared with saliva. --Shak.
      [1913 Webster]