complexity; degree of complication
Abstract noun derived from 複雑 (complex). Used to describe the state or degree of being intricate, involved, or difficult to understand.
I am amazed by the complexity of this problem.
The complexity of the system is increasing.
The complexity of the procedures is increasing.
The problem kept becoming more and more complex.
There is a need to reduce the complexity of the system.
It is difficult to understand the complexity of that problem.