Incoherent means impossible to understand because the parts don't fit together logically or clearly. When someone gives an incoherent explanation, their words jumble together without making sense, like trying to follow directions from someone who keeps changing the subject and leaving out important steps.

Imagine a friend trying to explain the plot of a movie but jumping randomly between scenes, forgetting key characters, and mixing up what happened when. Their story would be incoherent because you couldn't follow what actually happened. Or think of writing an essay without organizing your thoughts: one paragraph about dinosaurs, the next about video games, then back to dinosaurs again with no connection between ideas. The result would be incoherent.

Someone might become incoherent when extremely tired, upset, or confused, with words tumbling out in fragments that don't form complete ideas.

The opposite is coherent, meaning clear and logical. A coherent explanation flows smoothly from one point to the next, making sense throughout. When you organize your thoughts before speaking or writing, you're working to be coherent rather than incoherent.