When an inmate is charged with 18USC984 C what does that mean?

Title 18 of the United States Code (18 USC) covers crimes and criminal procedure in the United States. Section 984 specifically relates to smuggling of controlled substances into a penal or correctional institution. If an inmate is charged under 18 USC 984(c), it likely means they are accused of being involved in the smuggling of drugs into a prison or similar facility.