Inscrivez-vous ou connectez-vous pour rejoindre votre communauté professionnelle.
It means simply a bad quality source code with a complex and tangled control structure. Which make it hard to understand, to modify, to improve and uses extensively hardware resources.
Here is an example:
source code that has a complex and tangled control structure, especially one using many GOTO statements, exceptions, threads, or other "unstructured" branching constructs