Fenster writes:

Here’s something I did not know.  The word “gunsel” has two meanings. In its most common slang usage, it refers to a criminal carrying a gun.  But in earlier convict slang, the word had a quite different meaning:

gunsel

A young man kept for homosexual purposes; (street and prison slang). A passive partner in anal intercourse.

That’s quite a . . . ummm . . . stretch.  The explanation?

A plausible story of the way the word changed sense was set out by Erle Stanley Gardner in an article in the Atlantic Monthly in 1965. He claimed it was the fault of Dashiell Hammett. Together with Gardner, Raymond Chandler and others, he was a contributor to the old Black Mask pulp magazine edited by Joseph Shaw that featured naturalistic crime stories.

Can you find the gunsel?

But Shaw was dead against including vulgarisms and blue-pencilled some of Hammett’s underworld usages. To retaliate, as Gardner told the story, Hammett laid a trap for Shaw. In his next story he included the term gooseberry lay. Shaw pounced on this and rejected it, though it wasn’t a rude term at all but tramps’ slang for stealing washing off clotheslines to sell. But Hammett also included gunsel in the story, which Shaw left in, thinking it meant “gunman”.

The term derives from the Yiddish genzel, meaning little goose or gosling.

So in the spirit of connecting all the dots:

Gunsel 1

Gunsel 2