The Collaborative International Dictionary of English v.0.48:

Flagellate \Flag"el*late\, v. t. [imp. & p. p. Flagellated; p.
   pr. & vb. n. Flagellating.] [L. flagellatus, p. p. of
   flagellare to scoure, fr. flagellum whip, dim. of flagrum
   whip, scoure; cf. fligere to strike. Cf. Flall.]
   To whip; to scourge; to flog.
   [1913 Webster]