When it comes to expressing disinterest or apathy, there are plenty of synonyms to convey the sentiment of "I do not care." Some common phrases include "whatever," "it doesn't matter," "who cares," "not my problem," "I'm indifferent," and "I have no interest." Other idioms like "I couldn't care less," "it's all the same to me," and "I'm not bothered" also work. For a more sarcastic tone, try "I'm on the edge of my seat" or "I'm all ears." No matter the phrasing, these synonyms all communicate the same message of a lack of concern or attention.