The acronym WITD stands for "What In The World?". There are numerous synonyms for this phrase, including "what the heck", "what on earth", "what in God's name", "what in the universe", "what in the heavens", and "what in the cosmos". These all convey the same sense of disbelief or confusion at a situation or statement. Additionally, other related phrases such as "I can't believe it", "are you serious?", and "no way" can also convey a similar sentiment. In any case, these synonyms allow for a more diverse and nuanced expression of surprise or disbelief.