The Collaborative International Dictionary of English v.0.48:

Turndown \Turn"down`\ (t[^u]rn"doun`), a.
   1. Capable of being turned down; specif. (Elec.),
      Designating, or pertaining to, an incandescent lamp with a
      small additional filament which can be made incandescent
      when only a small amount of light is required.
      [Webster 1913 Suppl.]

   2. Made to wear with the upper part turned down; as, a
      turndown collar.
      [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

Turndown \Turn"down`\ (t[^u]rn"doun`), n.
   1. An act of refusing or of being refused; as, to get a
      turndown in an application for a job, a grant, etc.
      [PJC]

   2. A decline in activity, especially business; a downturn;
      as, they expect a turndown in housing construction in the
      fall.
      [PJC]

WordNet (r) 3.0 (2006):

turndown
    n 1: the act of refusing an offer; "the turndown was polite but
         very firm" [syn: nonacceptance, turndown]

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "turndown":
   abnegation, contradiction, declension, declination, declinature,
   declining, denial, deprivation, disagreement, disallowance,
   disclaimer, disclamation, disobedience, dissent, holding back, nay,
   negation, negative, negative answer, nix, no, nonacceptance,
   noncompliance, nonconsent, nonobservance, recantation, refusal,
   rejection, repudiation, retention, thumbs-down, unwillingness,
   withholding