Downhills are often associated with outdoor activities such as skiing, snowboarding, or mountain biking. However, there are numerous synonyms for this word that can be used to describe the incline of hills or mountains. Some of these synonyms include descents, declines, declivities, declines, slopes, and gradients. Each of these words can be used interchangeably to describe the downward direction in which a hill or mountain is inclined. When used in a sentence, choosing the right synonym can help to enhance the meaning or tone of the message being conveyed. For instance, declivity might be used to describe a very steep and sudden slope, while gradient might be used to describe a gradual incline.