The phrase "copping some z" refers to sleeping or taking a nap. Antonyms for this phrase would include words like "awake," "alert," and "energetic." Other antonyms might include words that suggest an activity or a state of being active, such as "working," "studying," or "exercising." Depending on context, antonyms might also include words that imply a lack of rest or relaxation, such as "stressed," "anxious," or "overwhelmed." Ultimately, the antonyms for "copping some z" will depend on the specific meaning and tone of the phrase within a particular sentence or conversation.