something complex or intricate
labyrinth - web
The word ‘labyrinth’ describes a complex structure that includes a large network of interlinking paths or passages which make it very hard to navigate. From this base meaning, it can also be adapted to express something that is very complicated and difficult to understand.
Inside the cave were a labyrinth of underground tunnels which were nearly impossible to explore.
The labyrinthine corridors of the building made it very easy to get lost, especially as I had never been there before.
Applying for a visa to that country turned out to be a labyrinth of forms and paperwork.