Merriam-Webster's Collegiate® Dictionary, 11th Edition
MOPE
I. intransitive verb (moped; moping)
Etymology: probably from obsolete mop, mope fool
Date: 1568
to act in a dazed or stupid manner, to give oneself up to brooding ; become listless or dejected, to move slowly or aimlessly ; dawdle , moper noun mopey adjective
II. noun
Date: 1693
one that mopes, blues 1