hang-dog (adj.)Related entries & more
also hangdog, 1670s, apparently "befitting a hang-dog," that is, a despicable, degraded fellow, so called either from being fit only to hang a dog (with construction as in cutthroat, daredevil) or of being a low person (i.e. dog) fit only for hanging. The noun, however, is attested only from 1680s.