Riffraff (noun)

1. People considered to be of low social or economic status, or who are considered undesirable or disreputable.
2. A group of people considered to be undesirable or disreputable.

Origin:

From the french word rif et raff, meaning "scraps and refuse" or "the dregs of society".

Examples:

1. The city center was filled with riffraff and vagrants.
2. The party was filled with wealthy people and the riffraff.
3. The riffraff on the streets were causing trouble.
4. The politician referred to the protesters as riffraff.
5. The bouncer kept the riffraff out of the club.