The Collaborative International Dictionary of English v.0.48:
Overmodest \O"ver*mod"est\, a. Modest to excess; bashful. -- O"ver*mod"est*ly, adv. [1913 Webster]WordNet (r) 3.0 (2006):
overmodest adj 1: affectedly modest or shy especially in a playful or provocative way [syn: coy, demure, overmodest]