When someone says they're "tickled to death," it means they're thrilled or extremely amused by something. However, there are many synonyms that can be used in its place. "Overjoyed" is a great word to use when you're very happy and excited. "Thrilled" can also be used to express joy and excitement, while "delighted" is a softer way to say you're pleased. "Ecstatic" is a perfect synonym for extreme happiness and is often used when something amazing happens. Finally, "elated" is a strong word, indicating intense happiness and a sense of great satisfaction or triumph. All of these words can be used as alternatives to "tickled to death" to describe those feelings of happiness and joy.