The phrase "is contingent" refers to something that is dependent on certain conditions or circumstances. There are a variety of synonyms that can be used to convey this meaning, such as "conditional," "subject to," "limited by," "reliant on," and "hinged on." Other similar phrases that can be used include "depends on," "rests on," "lies with," and "is determined by." These synonyms all capture the idea of something that is not certain or absolute, but rather relies on external factors in order to exist or succeed. By using these different terms, writers can add nuance and variety to their language, while also conveying a particular sense of contingency or dependence.