vt.

1. 使复杂化；使费解；使难对付
   The child's existence complicated matters considerably.

   这个小孩子的存在使问题大为复杂。

2. 并发（病）；使恶化[H]
   His disease was complicated by pneumonia.

   他的病因并发肺炎而加重。

3. 使卷入，使陷入，使牵连[H]

v.

1. make more complex or confusing.
2. Medicine  introduce complications in (an existing condition).