thrillers are less predictable and usually try to maintain tension throughout, whereas horror aims for a climax.
experience
thriller has more suspense and action and might not scare you, but horror can be slow yet still scary.
i think thriller movies have a more consistent plot; the story can exist without being scary. horror movies are only there to scare you, and the plot is less important/cohesive.
in the thriller, there is action. horror is not characterized by action, and one scene can unfold very slowly, whereas thrillers have a certain dynamism.
horror is more gory and graphic, whereas thriller relies on jump scares and focuses more on the atmosphere, such as suspense and surprise.
thriller is suspenseful and horror shows the gruesome stuff.
thriller films provide suspense, and we are excited to know what will happen in the next moments. additionally, we cannot predict the ending. the color palettes often change according to the mood and the scenes. however, when it comes to horror, most of the time the plot can be predicted, and it surprises us with the appearance of ghosts or creatures.
horror is basically just scary, spooky, insane, and fearful (like saw, texas chainsaw massacre, etc.). thrillers are less scary (that's the best explanation i have).
thriller is more psychological and suspenseful, while horror is more about gore and jump scares.
horror is only visual, thriller is mental.
horror creates a feeling of fear, whereas thriller is more intense.