"Unusual" is the perfect antonym for the word "am usual". "Am usual" refers to something that is normal or usual for a person, while "unusual" means something that is not normal or out of the ordinary. For instance, if a person is always punctual, their "am usual" behavior would be to arrive on time. However, if they are late for a meeting, it would be considered an "unusual" behavior for them. Similarly, a person who talks a lot can be considered as an "am usual" talker, while someone who rarely speaks can be regarded as an "unusual" talker. Therefore, "unusual" precisely defines the opposite of "am usual".