"Copped some Z" is a slang term used to indicate that someone has fallen asleep or is taking a nap. The word 'copped' is being used in a sense of acquiring or stealing. In contrast to this, the antonyms for the phrase can be identified as staying up, engaging in activity or keeping oneself awake. The word 'z' stands for the sound of snoring, which also indicates a state of deep sleep or rest. The antonyms for 'z' could be remaining alert or being restless. It is important to note that drowsiness and lack of rest can lead to serious health issues, which is why it is essential to ensure adequate sleep is achieved.