Definitions

1. noun

a word or phrase used to identify a member of a particular group or to signal that one is aware of a particular issue or controversy.

“The politician’s use of the word ‘evangelical’ as a sibboleth to describe her opponent was seen as a divisive tactic.”

2. noun

something that is considered to be a test or a marker of group identity or affiliation.

“Supporting the local sports team is a sibboleth of community loyalty.”