There are several synonyms for the phrase "watch the clock," which refers to the act of monitoring the time to ensure punctuality or to avoid boredom. One alternative is to "keep an eye on the time," which means to periodically check the clock or watch without getting too distracted. Another option is to "monitor the clock," which implies a more steady or continuous observation. "Track the time" is also a suitable synonym, as it emphasizes the importance of following the passing of time accurately. Lastly, "count down the minutes" describes a potentially impatient and focused approach to watching the clock, where each minute feels like an eternity.