When something is revolting, it is so unpleasant that you want to turn away from it. A smell, a taste, a sight, or even a cruel thing someone does can be revolting. It is stronger than just “bad” or “ugly”: it mixes dislike with a body feeling of pull-back, as if your stomach is turning. Friends say it freely; it is a sharp word to use about food on the table in front of you. Though actually, the same spelling is also just revolt + -ing, “fighting against a leader.” “The people were revolting” can mean they were rising up — or, as a joke, that they were disgusting. English speakers like that joke. Before a noun (a revolting smell, a revolting idea), people almost always mean the disgusting sense.