• mortel horror,
• mortol horror,
• mortil horror,
• mortul horror,
• morrtal horror,
• mortaal horror,
• mortall horror,
• mortle horror,
• mortlo horror,
• mortll horror

The adjective form of "mortal horror" is "horrifying".

The plural form of "mortal horror" remains the same: "mortal horror".

The singular form of the word "mortal horror" is "mortal horror". The word "mortal" is an adjective meaning "causing or liable to cause death; fatal" and "horror" is a noun indicating "an intense feeling of fear or shock". Together, "mortal horror" refers to extreme fear or horror that is capable of causing death. It does not have a distinct singular form.