When it comes to expressing the notion of being "subordinate to" someone or something, there are several synonyms that can be used in place of this phrase. These include synonyms such as "inferior", "secondary", "lower-ranking", "subsidiary", "subservient", "under", "subject to", "dependent on", "lesser", and "junior". These words are often used to describe a situation where one person or group is placed in a position of lesser authority or importance, such as an employee who is lower-ranking than their supervisor or a country that is dependent on a larger nation. Ultimately, the choice of synonym will depend on the context and intended meaning of the sentence.