super-maximum
/ˌs(j)uːp(ə)rˈmaksɪməm/originally and chiefly US
adjective
1Greater than the expected or conventional maximum; extremely or exceptionally high, large, etc.
2Designating a prison or part of a prison having super-maximum security measures, and intended for particularly dangerous prisoners.
- Now often shortened to super-max..
Origin
Early 20th century. From super- + maximum.