The phrase "subject to" is often used to denote a condition or requirement that must be met in order for something to occur. Synonyms for "subject to" include contingent upon, dependent on, governed by, subjected to, vulnerable to, and dictated by. These terms all carry a similar meaning of being influenced or controlled by something external. For instance, if you were to say that a proposal is contingent upon funding, this would indicate that the proposal is dependent on receiving funding in order to be successful. Similarly, if you say that a person is vulnerable to disease, this means that they are susceptible to catching illnesses. Regardless of the specific synonym used, all of these words help to convey the idea of something being subject to external factors or conditions.