What is a group of Thieves called?

A group of thieves is commonly called a Gang. Other collective nouns you may see include Mob and Pack.

A collective noun for thieves is a "gang," emphasizing the collaborative and unified nature of a group of individuals involved in criminal activities. Just like any collective noun, a gang contains several individual members who work together under a common purpose. Operating with a degree of organization and structure, this tight-knit unit of thieves, often portrayed in popular culture and literature, collaborates to plan and execute various criminal endeavors ranging from petty thefts to high-stakes robberies. Within a gang, the members display a clear hierarchy and division of labor, each contributing their unique skills to the success of the group's illicit objectives. These individuals are skilled in the arts of deception, stealth, planning, and execution, employing their collective knowledge and expertise to carry out robberies with efficacity. They may have different roles, such as scouts who observe potential targets or strongmen who handle physical confrontations if necessary. Collective nouns such as "gangs" not only suggest the unity of these thieves but also embody notions of secrecy, loyalty, and underworld relationships. Operating within their own microcosm, a gang sees itself as a tight bond reliant on mutual trust, where loyalty is valued and betrayal is met with grave consequences. The collective nature of the noun also reflects their ability to form resilient internal systems, including codes, signals, or secret hideouts, which aid their illegal endeavors. Although the activity of such individuals is entirely illegal and reprehensible, collective nouns like "gang" pique human fascination as they evoke images of intrigue, camaraderie, and the potential for daring escapes and crime-solving escapades. Even though thieves are seen as society's miscreants, the collective noun helps portray them not just as individuals operating in isolation, but as connected entities striving together to accomplish their ill-gotten gains.