The phrase "got idea" implies that someone has come up with a concept or plan. However, there are many antonyms that express the opposite sentiment. Rather than having an idea, one might be experiencing confusion, uncertainty, or even apathy. Instead of "got idea," one could say "lost idea" or "lack idea." Other options include "unclear" or "undecided." These antonyms can help to convey a different tone or meaning in a sentence, depending on what message the speaker wants to get across.