Stomach turning is an expression used to describe something that is so unpleasant or distasteful that it causes a feeling of revulsion. This feeling can be caused by two words: ICKY and SOUR. ICKY is an adjective used to describe something that is disgusting, repulsive, or unpleasant. SOUR is an adjective used to describe something that has a sharp, acidic taste. Together, these two words can be used to describe something that is so unpleasant that it turns one's stomach.