Alky

Alky is a term with several distinct uses in everyday language and in science, and its meaning depends on the context. In colloquial speech, alky (also spelled alkie or alky) is a British and Australian slang term for someone who habitually drinks alcohol or who is considered intoxicated. It can be used descriptively or pejoratively in casual writing and dialogue, and its connotation varies with tone and setting.

In chemistry and chemical engineering, alky is sometimes used as an informal shorthand for alkyl or alkylated compounds. An alkyl group is a hydrocarbon substituent derived from an alkane by removing one hydrogen atom, typically represented as R-. Alkyl groups such as methyl or ethyl are common building blocks in organic synthesis, and compounds described as alkylated have had hydrogen replaced by an alkyl group. In industrial contexts, the term alkylation refers to a process that attaches alkyl groups to molecules or to the production of alkylate, a high-octane gasoline blending component produced in refinery alkylation units. In these technical settings, formal terms like alkyl and alkylate are preferred, but shorthand forms occasionally appear in notes or internal communications.

Etymology reflects these two paths: the slang sense likely derives from connections to alcohol consumption, while the chemical sense derives from the term alkyl. The two uses are otherwise unrelated.

See also: alkyl, alkylation, alkane, alcohol.