The two meanings are believed to have originated concurrently but independently. gunsel: Or: gonsil/ gonzel/ gonsel: A 19th century term of German and Yiddish (little goose) derivation for a young, inexperienced gay male similar to the more recent gay slang term, “twink.” See sodomite for synonyms. The latter usage — a gun-toting hoodlum — derives from Dashiell Hammett’s The Maltese Falcon. Hammett’s publisher at the time refused to allow any rude or profane terminology in his publication. Hammett slipped in “gunsel” — a street term for a young, gay man — as a joke. Since it is used throughout the book to refer to the character of Wilmer — a gun-toting thug — most people erroneously assumed that is what it meant and it stuck.He seems to think he is quoting me, but no, I never heard it before. The language apparently comes from the Wiktionary discussion page. The view gains support from the estimable Michael Quinion, who adds a further surprising fillip:
See id. for "gooseberry lay." Accord, William Safire, with a cute anecdote about James Carville.
In Australia an equally extraordinary but different shift in sense has taken place. In the spelling gunzel it means a railway or tramway enthusiast (otherwise in various countries a railfan, trainspotter or gricer). In early appearances it referred to the kind of scruffy, obsessive and over-enthusiastic fan who travels with notebooks and cameras and who would bore you to tears with arcane information if you let him get started. The new meaning is said to have grown up at the Sydney Tramway Museum in the 1960s through the reading of old American comics. These days, I am told, the term is worn with pride.