The antonyms for the phrase "kept watch" can vary depending on the context of its use. Some possible antonyms include neglect, ignore, disregard, abandon, or overlook. When someone is actively keeping watch, they are attentive, vigilant, and alert to changes in their surroundings. Conversely, neglecting or ignoring something means to pay no attention to it. Disregarding something means to treat it with indifference, abandonment suggests leaving something completely unattended, and overlooking something means failing to notice its existence. Thus, depending on the situation, the opposite of keeping watch can take on different meanings and implications.