The Collaborative International Dictionary of English v.0.48:
Whipping \Whip"ping\, a & n. from Whip, v. [1913 Webster] Whipping post, a post to which offenders are tied, to be legally whipped. [1913 Webster]WordNet (r) 3.0 (2006):
whipping post n 1: post formerly used in public to which offenders are tied to be whipped