There are several synonyms that can be used instead of "study at happy." One such synonym is "learn with pleasure." This phrase conveys the same positive sentiment as "study at happy," highlighting the idea that learning can be enjoyable. Another synonym is "engage in joyful education," which emphasizes the active nature of the learning process. Additionally, one could use the phrase "pursue knowledge with joy" as a more formal alternative to "study at happy." Ultimately, any phrase that highlights the positive aspects of learning, such as enjoyment and fulfillment, can be used as a synonym for "study at happy".