shame·faced 
(shāmfāst′)
(shāmfāst′)adj.
1. Indicative of shame; ashamed: a shamefaced explanation.
2. Extremely modest or shy; bashful.
[By folk etymology from obsolete shamefast, bashful, ashamed, from Middle English, from Old English sceamfæst : sceamu, shame + fæst, fixed; see FAST1.]
shamefac′ed·ly (-fā′sĭd-lē) adv.
shamefac′ed·ness n.