Membership of any organisation not open to the public without formal membership and commitment to allegiance and which has secrecy about rules and membership or conduct
Aelodaeth o unrhyw sefydliad nad yw’n agored i’r cyhoedd heb ymaelodi’n ffurfiol ag ef ac sydd â llw teyrngarwch ac sy’n gyfrinachol o ran rheolau ac aelodaeth neu ymddygiad.