something that makes a situation more difficult, or the act of doing this

Dave couldn't find his passport at the airport and then there were further complications when Fiona lost her baggage. 戴夫在机场找不到护照了，而后事情越发麻烦，菲奥娜又把行李给丢了。

If any complications arise, let me know and I'll help. 如果发生什么麻烦事，告诉我一声，我会帮忙的。

an extra medical problem that makes it more difficult to treat an existing illness

If there are no complications, the doctor says that she'll be able to come home within two weeks. 如果没有并发症的话，医生说她两周内就可以出院了。