Screechiness is a word that describes a high-pitched, unpleasant, and harsh sound. However, there are several other words that can be used in place of screechiness to describe similar sounds or situations. Shrillness is a common synonym for screechiness that describes a piercing or high-pitched sound. Stridency is another similar word that describes an unpleasantly loud or harsh sound. Discordance is a word that can be used to describe a lack of harmony or synchronization in sounds, which is similar to screechiness. Other synonyms for screechiness may include grating, piercing, jarring, or cacophonous, depending on the context in which the word is being used.