From 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]
From The Collaborative International Dictionary of English v.0.48:
Swab \Swab\, n. [Written also swob.] 1. A kind of mop for cleaning floors, the desks of vessels, etc., esp. one made of rope-yarns or threads. [1913 Webster]
2. A bit of sponge, cloth, or the like, fastened to a handle, for cleansing the mouth of a sick person, applying medicaments to deep-seated parts, etc. [1913 Webster]
3. (Naut.) An epaulet. [Sailor's Slang] --Marryat. [1913 Webster]
4. A cod, or pod, as of beans or pease. [Obs.] --Bailey. [1913 Webster]
5. A sponge, or other suitable substance, attached to a long rod or handle, for cleaning the bore of a firearm. [1913 Webster]