Abseil is a word that refers to the process of descending a vertical surface using ropes and a harness. The word is commonly used in outdoor activities such as rock climbing, mountaineering, and cave exploring. However, there are several synonyms that can be used instead of abseil. Some of the most common synonyms are rappelling, descending, lowering, and scaling down. All these words symbolize lowering oneself down from a height. However, the word rappelling is the closest synonym to abseiling as it refers to the exact same process of descending using ropes and a harness.