Offensive odour, also known as a 'STENCH' (6 letters), is an unpleasant smell that can be caused by a variety of sources. It is often associated with bacteria, mold, and other contaminants in the air. The smell can be so strong that it can cause physical discomfort and even nausea. Offensive odours can be caused by a variety of sources, including sewage, garbage, smoke, and chemical spills. In some cases, the smell can linger for days or weeks, making it difficult to live in the affected area.