billy
n. uncountable C2 Proficiency US //ˈbɪɫi// UK //bˈɪli// bil·ly
n. a slang name for the drug amphetamine. People use this word in very casual or street settings.
n. a slang term for amphetamine, typically used in the United Kingdom and Australia. Highly informal in register and restricted to colloquial or drug-related contexts.
He was arrested for carrying a small bag of billy.
The police found several grams of billy hidden in the back of the suspect's vehicle during the search.
While the term is widely recognised in certain subcultures, using billy in a formal setting would be entirely inappropriate due to its strong association with illegal substance use.
Diminutive and pet-form; from Bill + -y.
Usage
Uncountable when referring to the substance; primarily British and Australian slang.