In a roundabout manner, this word means that behavior is accepted by others without being acknowledged or expressed. In other words, it's done by consent. Tacit approval can have positive as well as negative consequences. It allows bad behavior to go unpunished but also prevents others from taking action to correct it. In the novel Lord of the Flies, tacit approval is what allows the boys to play God over their stranded island adventure. Without it, they would never have been able to kill the pig or build the raft. However, such behavior cannot last forever, and when they run out of things to do or people to bully, they are going to have to deal with the fact that they are now facing reality. Tacit acceptance is important in groups of any size because it shows that no one is willing or able to take control. This makes it hard for anyone who might want to do something good to communicate their ideas or plans without fear of opposition. In conclusion, "tacit" means behavior is accepted by others without being acknowledged or expressed.