The word oscitant means being sleepy or drowsy, and its antonyms bring some lively and energetic terms to the vocabulary. Alert, wide-awake, and attentive are a few of the antonyms that can be used in place of oscitant. These words signify the opposite end of the spectrum, conveying excitement, alertness, and vigilance. Other antonyms that can be used in place of oscitant include attentive, active, energetic, enthusiastic, lively, and vibrant. By using these antonyms, writers and readers can add contrast to their sentences and ultimately give more depth and nuance to their expressions.