Disturber
/dɪˈstɜːrbər/
Definition 1 of 2
Pro Tip 1/3Contextual Use
Used to highlight negative impacts in social or controlled settings. 
A ringing phone is a disturber during a cinema screening.
Pro Tip 2/3Connotative Nuance
Implies annoyance or inconvenience caused by the interruption. 
The street performer became an unexpected disturber of our conversation.
Pro Tip 3/3Cultural Context
May refer to actions seen as disrespectful in certain cultures. 
In the library, loud talkers are seen as disturbers of public etiquette.