Nikki is a colloquial term for the drug nicotine. It is quite common for drugs to be personified with female names like Molly or Mary Jane. This particular slang gained traction following the release of rapper Logic's song titled "Nikki."
Logic Nikki Meaning
Rapper Logic's song "Nikki" explores his complex relationship with nicotine, where he raps, "I’m addicted to this sh*t like it was hard drugs - Nikki baby I love you but now I gotta go." The lyrics illustrate Logic's intense attachment to nicotine, while acknowledging the toxicity of this dependency and his desire to break free.