When we talk about keeping watch, it usually means the act of observing or monitoring a particular situation or place. Some synonyms that can be used instead of keeping watch are (1) vigilance, which means being watchful and alert; (2) surveillance, which is the act of observing or monitoring a specific location or activity; (3) oversight, which refers to the responsibility of supervising or managing something; (4) watchfulness, which implies being attentive and mindful of any changes or threats; (5) scrutiny, which means a detailed examination or investigation of something. Overall, these synonyms convey the importance of being vigilant and alert when keeping watch over something or someone.