Stumer

A Stumer is an expression used commonly to denote a shell that had failed to explode. Also used as a question, "Is that a stumer?" of German gas-shells, it being a common enemy practice to include gas shells in a salvo. The others burst on impact and whether those apparently "dud" were really so, or gas shells about to open and let out the deadly gas, was the question. Used also to describe a "rotter" - someone that is no good or incompetent; any kind of failure.