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 ME rif and raf every particle, things of small value < OF rif et raf, formed on rifler to spoil (see rifle2), raffler to ravage, snatch away
[Middle English riffe raffe, from rif and raf, one and all, from Anglo-Norman rif et raf, rifle et rafle : Old French rifler, to rifle; see rifle2 + Old French raffler, to carry off (from raffle, act of seizing; see raffle1).]