Source : Webster's Revised Unabridged Dictionary (1913)

Overmodest \O"ver*mod"est\, a.
   Modest to excess; bashful. -- {O"ver*mod"est*ly}, adv.

Source : WordNet®

overmodest
     adj : affectedly modest or shy especially in a playful or
           provocative way [syn: {coy}, {demure}]