Answer: - Cheating in selling and buying, by hiding the defect in the commodity

- Cheating in learning, like the students' cheating on exams

- Cheating in speaking, like in false testimony and lying

- Breaching one's agreements with others

The prohibition of cheating is clear in the Hadīth stating that the Messenger of Allah (may Allah's peace and blessings be upon him) once came upon a heap of food, and when he put his hand into it, his fingers felt some dampness. So, he asked: "What is this, O owner of the food? The man replied: "Rain had fallen on it, O Messenger of Allah," whereupon the Prophet (may Allah's peace and blessings be upon him said: "Why did you not put the damp part on top of the food so that people might see it? He who cheats has nothing to do with me." [Narrated by Muslim]

"Heap of food": a pile of food.