There are various synonyms for the phrase "get sleepy" which can be used in different contexts to convey the same meaning. Some of the synonyms include "feel drowsy", "become groggy", "get tired", "doze off", "nod off", "fall asleep", "snooze", "slip into slumber," and more. These synonyms can be used interchangeably depending on the situation or the tone of the context. For instance, "feel drowsy" can be used for a more formal tone, while "doze off" and "nod off" are more colloquial in nature. Overall, these synonyms help to add variation to our vocabulary and prevent us from using the same repetitive words and phrases.