It was reported this week that the shadow trade secretary, Barry Gardiner, had called the Good Friday agreement a “shibboleth”. Critics pounced on social media, complaining that Gardiner didn’t know what the word meant. But did anyone?

Shibboleth is the Hebrew for either “ear of corn” or “stream in flood”. In the Bible, Jephthah uses the word to identify his enemies, the Ephraimites, because they can’t pronounce the “sh”. Hence a “shibboleth” became a test-word to identify members of an in-group, and then a custom or habit specific to a group. Since the 1930s, however, “shibboleth” has also meant simply an outdated view, probably deriving from the original sense via the idea of an opinion held by tribal custom rather than by reasoning.

Gardiner himself apologised for causing a “misunderstanding” and creating “the impression that I thought the Good Friday agreement was in any way outdated or unimportant”. Since that is the only thing he could possibly have meant, it is unclear just who had misunderstood what. Perhaps total avoidance of the word “shibboleth” should be a shibboleth for future members of the shadow cabinet.