a group of people at a meeting or an event who have something in common, especially the place they come from, that is not shared by other people at the event (Oxford)
2. a group of people representing an organization or country, or a part of a military force .(Cambridge)
The largest contingent was from the United States. .(Oxford)
we saw a large contingent of voluntary soldiers .(Cambridge)
largest contingent
a large contingent of voluntary soldiers
Unanticipated
Unexpected
Unpredictable
Planned
Definite
Contingently