The Collaborative International Dictionary of English v.0.48:

Slumber \Slum"ber\, v. i. [imp. & p. p. Slumbered; p. pr. &
   vb. n. Slumbering.] [OE. slombren, slumberen, slumeren, AS.
   slumerian, fr. sluma slumber; akin to D. sluimeren to
   slumber, MHG. slummern, slumen, G. schlummern, Dan. slumre,
   Sw. slumra, Goth. slawan to be silent.]
   1. To sleep; especially, to sleep lightly; to doze. --Piers
      Plowman.
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            He that keepeth Israel shall neither slumber nor
            sleep.                                --Ps. cxxi. 4.
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   2. To be in a state of negligence, sloth, supineness, or
      inactivity. "Why slumbers Pope?" --Young.
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