Incoherence is a quality of being unclear, disjointed, or nonsensical. The incoherence of the scavenger hunt's instructions resulted in everyone running in different directions looking hopelessly confused.
A political candidate's incoherence usually hurts their chances of winning an election, since no one really understands what they stand for. And if your English teacher comments on the incoherence of your latest essay, you might want to get some extra writing help. When ideas, words, or thoughts don't hold together quite right, that's incoherence. The Latin root is cohaerere, "stick together."