Nutty about refers to a strong liking or passion for something or someone. The antonyms for this phrase include indifferent, disinterested, apathetic, unconcerned, uninterested, and nonchalant. These words imply a lack of enthusiasm, excitement, or interest. When someone is indifferent or disinterested, they might not have any opinion at all about what is being discussed. On the other hand, when someone is nonchalant, they are typically cool, calm, and collected, and they might not express any strong emotions even when they have a strong opinion. These antonyms provide a contrast to the positive connotations of nutty about and convey a negative or neutral emotional state.