The slang term "nonce," chiefly used in Britain, is a derogatory term referring to a person who is an alleged or convicted sex offender, particularly one guilty of sexual offenses involving children. It is often used as prison slang and can include meanings such as a pedophile or child molester. The term carries a strong stigma and is a severe insult in British slang. The term "nonce" also has other non-slang meanings, such as in cryptography (a value used once) and in linguistics (a word coined for a single occasion), but in the context of British slang, it specifically denotes sexual offenders against children. There are some proposed origins of the slang use linked to dialect words or as a backronym ("Not On Normal Communal Exercise"), but these are less certain. The slang use is described as highly derogatory and specific to the criminal or prison context. In summary, in British slang, "nonce" means a sex offender, especially involving children. This is its primary slang usage today. This explanation is based on British slang definitions from several sources including the Cambridge Dictionary and other linguistic references.