Complicate (verb)

1. To make (something) more complex, involved, or difficult.
2. To involve in a complicated situation.
3. To mix together in a confused or involved manner.

Origin:

From latin complicare, meaning "to fold together".

Examples:

1. The new regulations complicated the process of getting a license.
2. His sudden disappearance complicated the investigation.
3. The situation was already complicated and the new information only made it worse.
4. Her explanation complicated the simple matter even more.
5. The knot was so complicated that it took him several minutes to undo it.