However, you could use prefixes like:
* Mandatory: Meaning required by law or rule.
* Obligatory: Meaning required or demanded by a moral or legal obligation.
* Required: Meaning needed or demanded.
* Essential: Meaning absolutely necessary.
* Forced: Meaning compelled to do something against one's will.
Examples:
* Mandatory education
* Obligatory military service
* Required attendance
* Essential training
* Forced labor
Ultimately, the best prefix depends on the specific context and nuance you want to convey.