1560s, "to move and act unconsciously;" 1580s, "to be listless and apathetic," the sound of the word perhaps somehow suggestive of low feelings (compare Low German mopen "to sulk," Dutch moppen "to grumble, to grouse," Danish maabe, dialectal Swedish mopa "to mope"). Related: Moped; moping; mopey; mopish.[mope etymology, mope origin, 英语词源]