The word "SUX" has become a popular slang term used to express disappointment or annoyance. However, it's important to find other synonyms to use in professional and formal settings. Some common synonyms for "SUX" include "stinks," "disappoints," "fails," "underwhelms," "dismays," "frustrates," "irritates," "bothers," and "vexes." These synonyms can be substituted in place of "SUX" to communicate negative feelings more effectively without resorting to crass language. Additionally, using more descriptive words can enhance the specificity and clarity of your message, making it easier for others to understand your point of view.