1540s, "excessively modest, shy and sheepish," with -ful + baishen "to be filled with consternation or dismay" (mid-14c.), from Old French baissier "bring down, humiliate" (see abash). An unusual case of this suffix attached to a verbal stem in the passive sense. Related: Bashfully; bashfulness (1530s).
updated on April 08, 2017