Mob diplomacy is not a commonly used term in diplomacy. The term originated during the Renaissance period, when powerful families in Italy would send large groups of people to support their diplomatic efforts in foreign states. So it is likely that the term refers to a negative phenomenon in which a group of people, often with a shared grievance or agenda, use intimidation, violence, or other coercive tactics to influence or intimidate government officials or other actors in the diplomatic process.
In this context, mob diplomacy could be seen as a form of ‘street diplomacy’, in which individuals or groups seek to advance their interests through non-traditional, often disruptive means. Such behaviour is generally frowned upon in diplomatic circles and is not considered a legitimate means of pursuing diplomatic objectives.