The Collaborative International Dictionary of English v.0.48:

Setdown \Set"down`\ (s[e^]t"doun`), n.
   The humbling of a person by act or words, especially by a
   disparaging remark, a retort or a reproof; the retort or the
   reproof which has such effect. Also called put-down.
   [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

put-down
    n 1: a crushing remark [syn: put-down, squelch, squelcher,
         takedown]