riffraff
n. <貶>烏合之眾,群氓,<方>渣滓; 痞子; 痞
If you refer to a group of people as riff-raff, you disapprove of them because you think they are not respectable.
1. disparaging terms for the common people
THE " MOVEMENT OF THE RIFFRAFF "
所謂 “ 痞子運動 ”
The army should strictly discipline riffraff.
部隊要嚴格管教那些兵油子.