"Enforced," "compelled," and "coerced" are all effective synonyms for the phrase "forced upon." "Enforced" implies the use of authority to ensure compliance, such as in the case of laws or rules. "Compelled" conveys a sense of pressure or obligation, as if the person or group had no other alternative. "Coerced," on the other hand, suggests a more forceful approach, often involving threats or physical intimidation. Other possible synonyms include "imposed," "dictated," and "thrust upon," each of which conveys a sense of something being foisted upon someone without their consent or agreement.