ADJ-GRADED
(问题)棘手的，复杂难解的，令人头疼的
If you describe a problem as thorny, you mean that it is very complicated and difficult to solve, and that people are often unwilling to discuss it.
例句
...the thorny issue of immigration policy...
移民政策这个棘手问题
It is essential that we tackle this thorny problem.
我们很有必要处理这个棘手问题。