The antonyms for "become unconscious" are to become aware or conscious. To be conscious is to be aware of one's surroundings and thoughts, and to have a sense of perception. There are also several degrees of consciousness, including full and partial awareness. An individual can become aware through many means, from a sudden shock to a gradual emergence from sleep. Being aware can be likened to being awakened from a deep sleep, and it is often a positive experience. Regardless of how one becomes aware, it is a sign of mental clarity, perception, and attentiveness. So, being aware and conscious is the opposite of becoming unconscious.