The Collaborative International Dictionary of English v.0.48:

Mop \Mop\, v. t. [imp. & p. p. Mopped; p. pr. & vb. n.
   Mopping.]
   To rub or wipe with a mop, or as with a mop; as, to mop a
   floor; to mop one's face with a handkerchief.
   [1913 Webster]