The Collaborative International Dictionary of English v.0.48:

Flog \Flog\ (fl[o^]g), v. t. [imp. & p. p. Flogged (fl[o^]gd);
   p. pr. & vb. n. Flogging (-g[i^]ng).] [Cf. Scot. fleg blow,
   stroke, kick, AS. flocan to strike, or perh. fr. L.
   flagellare to whip. Cf. Flagellate.]
   To beat or strike with a rod or whip; to whip; to lash; to
   chastise with repeated blows.
   [1913 Webster]