people, or a group of people, regarded as disreputable or worthless: a pack of riffraff.
2.
the lowest classes; rabble: the riffraff of the city.
3.
trash; rubbish.
adjective
4.
worthless, disreputable, or trashy.
Origin: 1425–75;late Middle Englishrif and raf every particle, things of small value < Old Frenchrif et raf, formed on rifler to spoil (see rifle2), raffler to ravage, snatch away
c.1470, from earlier rif and raf "one and all, every scrap" (1338), from O.Fr. rif et raf, from rifler "to spoil, strip" (see rifle (v.)) and raffler "carry off," related to rafle "plundering" (see raffle).