Harshness is a word that describes a quality of being severe, rough, or unkind. However, there are a number of synonyms that can be used in its place to describe a similar quality. Words like austerity, severity, toughness, and rigidity can all convey a sense of brutal harshness. Similarly, acerbity, acrimony, bitterness, and hostility suggest a more aggressive or negative form of harshness. Alternatively, words like bluntness, directness, and outspokenness might be used to describe a quality that is more honest or straightforward, but which can still come across as harsh depending on the situation. Ultimately, the choice of synonym will depend on the context in which it is used, as well as the tone and style of the writing.