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.

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®

shamefaced
     adj 1: extremely modest or shy; "cheerfully bearing reproaches but
            shamefaced at praise"- H.O.Taylor
     2: showing a sense of shame [syn: {sheepish}]
     3: showing a sense of guilt; "a guilty look"; "the hangdog and
        shamefaced air of the retreating enemy"- Eric Linklater
        [syn: {guilty}, {hangdog}, {shamed}]