"Illicit use" refers to the unauthorized or illegal use of something. It means using or employing something in a way that is prohibited, not allowed, or against the law. Full definition
Would that help prevent illicit use of the signals — and I don't mean just the use without permission, but the use in actual unlawful communications activity such as mentioned above? (slaw.ca)
Sue pharmaceutical opioid distributors for violating «their duty by selling large amounts of painkillers that were then diverted for illicit uses, helping to contribute to the opioid epidemic.» (amny.com)
Levin is the cofounder of Chainalysis, a startup that tracks virtual currency movement and investigates illicit use. (fortune.com)