Source : Webster's Revised Unabridged Dictionary (1913)

Shamefaced \Shame"faced`\, a. [For shamefast; AS. scamf[ae]st.
   See {Shame}, n., and {Fast} firm.]
   Easily confused or put out of countenance; diffident;
   bashful; modest.

         Your shamefaced virtue shunned the people's prise.
                                                  --Dryden.

   Note: Shamefaced was once shamefast, shamefacedness was
         shamefastness, like steadfast and steadfastness; but
         the ordinary manifestations of shame being by the face,
         have brought it to its present orthography. --Trench.
         -- {Shame"faced}, adv. -- {Shame"faced`ness}, n.

Source : WordNet®

shamefacedness
     n : feeling embarrassed about yourself [syn: {sheepishness}]