The Collaborative International Dictionary of English v.0.48:

Courtesy \Courte"sy\, v. i. [imp. & p. p. Courtesied
   (-s[i^]d); p. pr. & vb. n. Courtesying.]
   To make a respectful salutation or movement of respect; esp.
   (with reference to women), to bow the body slightly, with
   bending of the knes.
   [1913 Webster]