The phrase "is up" can have various synonyms based on the context. When referring to prices or values, words like "increased," "escalated," "surged," or "skyrocketed" can be used. For example, "the stock prices surged" or "the temperature escalated." When referring to someone's mood or overall state, words like "elated," "energized," "excited," or "animated" can be used. For instance, "she was elated after receiving good news" or "the crowd was excited when the band started playing." Alternatively, when referring to something becoming available, words like "available," "accessible," or "open" can be used. For example, "the reservation system is open now".