The phrase "am big about" typically refers to something that a person is passionate or enthusiastic about. To find antonyms for this phrase, we can explore words that describe the opposite of passion and enthusiasm. Some antonyms for "am big about" could include "dislike", "apathy", "indifference", "disinterest", "boredom", and "detachment". While being big about something may bring excitement and motivation, being the opposite can imply a lack of interest or investment. It's important to consider both sides of the coin and assess what we truly care about in life.