Definition: In this task, you need to generate an appropriate title for the given summary of some paragraph. The generated title must be short and should include the main topic of the given text. Your summary should be less than 20 words long.
Input: The complex web of paramilitary gangs, security and intelligence forces, agents and informers, in Northern Ireland during the years of conflict were not a consideration for dictionary compilers when they wrote the entry for collusion.

How has collusion been defined?