The Collaborative International Dictionary of English v.0.48:

Swab \Swab\, v. t. [imp. & p. p. Swabbed; p. pr. & vb. n.
   Swabbing.] [See Swabber, n.]
   To clean with a mop or swab; to wipe when very wet, as after
   washing; as, to swab the desk of a ship. [Spelt also swob.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Swob \Swob\, n. & v.
   See Swab.
   [1913 Webster]

WordNet (r) 3.0 (2006):

swob
    n 1: cleaning implement consisting of absorbent material
         fastened to a handle; for cleaning floors [syn: swab,
         swob, mop]
    v 1: wash with a swab or a mop; "swab the ship's decks" [syn:
         swab, swob]
    2: apply (usually a liquid) to a surface; "dab the wall with
       paint" [syn: dab, swab, swob]