What is another word for most on call?
Pronunciation: [mˈə͡ʊst ˌɒn kˈɔːl] (IPA) 
The term "most on call" refers to the individual or group that is most readily available to respond to emergency situations or urgent requests. Some synonyms for this term include "most accessible," "most responsive," and "most available." Other similar phrases may include "first responders," "emergency responders," and "on-duty personnel." These terms are often associated with professions such as firefighters, paramedics, and law enforcement officials who are responsible for promptly responding to emergency situations. In business settings, the term "on-call team" may be used to describe a group of individuals who are available to address any urgent needs or requests that may arise outside of typical business hours.
