A stopgap is something that fills a gap until the real answer comes. A stopgap measure, only a stopgap, a stopgap solution.
Calling something a stopgap is a promise that it is temporary, and the joke is how many turn out not to be. It works as an adjective too — stopgap funding. The image is literally stopping a gap in a wall or a hedge.
1nounstopgapSomething that fills a gap until a real answer comes.
“The portable heaters are only a stopgap until the new boiler is installed.”
stopgap is a temporary measure.
From the phrase to stop a gap, meaning to fill a hole in a wall or hedge.
The noun is derived from stop + gap, from the phrase to stop a gap. The adjective is from an attributive use of the noun, and the verb is derived from the noun.
Etymology from Wiktionary, CC BY-SA