1. people who muck out stables or do dirty manual work
Usage: informal
2. people who cause trouble or behave badly
Usage: informal; chiefly British

Examples

• The stable muckers arrived early to clean the horse stalls.
• He hired several muckers to help with the construction cleanup.
• The teacher had to deal with a group of muckers disrupting class.
• Those muckers were throwing stones at windows again.
• The farm employed muckers during the busy harvest season.
• Local muckers were causing problems in the neighborhood.