sudden irruption 突然闯入
mass irruption 大规模涌入
irruption of birds 鸟类的突然迁徙
A: Did you see the irruption of the crowd at the gate?
A：你看到人群突然冲向大门了吗？
B: Yes, it was so sudden that nobody could stop them.
B：是的，太突然了，没人能挡住他们。
1) 突然的闯入或入侵
2) 某种事物（如疾病、情绪、动物）的突然爆发或出现
3) 大量人群或物体的涌入
1. 突然的闯入；爆发
noun
1. A sudden, violent, or disruptive entrance or breaking in.
Synonym: invasion, eruption, influx