impermissibleim‧per‧mis‧si‧ble /ˌɪmpɜːˈmɪsəbəl $ -ɜːr-/ adjective formal

- The conduct of the officers in this case was impermissible.
- Codes of conduct were beginning to emerge and a range of permissible and impermissible subjects was being informally drawn up.
- I consider that such doctrine would be dangerous and impermissible.
- To switch off the respirator otherwise is impermissible.
nounpermissionpermitpermissivenessadjectivepermissible ≠ impermissiblepermissiveverbpermit