Strongest:
* Abhorrence: A feeling of extreme repugnance or aversion.
* Abomination: Something that causes extreme disgust or hatred.
* Detestation: Intense dislike or hatred.
* Contempt: The feeling that someone or something is worthless or despicable.
Moderate:
* Aversion: A strong dislike or disinclination.
* Disgust: A feeling of revulsion or strong disapproval.
* Repugnance: A strong feeling of distaste or aversion.
* Antipathy: A strong feeling of dislike or aversion.
More specific:
* Scorn: Open or expressed contempt for someone or something.
* Revulsion: A feeling of intense disgust or horror.
* Horror: A feeling of intense fear, dread, or loathing.
* Disdain: A feeling of superiority or contempt.
Figurative:
* To turn one's stomach: To cause intense revulsion.
* To make one's skin crawl: To cause a feeling of intense uneasiness or disgust.
* To be sickened by: To be disgusted or revolted by something.
The best synonym for "loathing" will depend on the specific context and the intensity of the feeling you want to express.