nonce

Meanings

Noun

• The one or single occasion; the present reason or purpose (now only in for the nonce).
• A nonce word.
• A value constructed so as to be unique to a particular message in a stream, in order to prevent replay attacks.
• A sex offender, especially one who is guilty of sexual offences against children.
• A pedophile.
• A police informer, one who betrays a criminal enterprise
• A stupid or worthless person.

Adjective

• One-off; produced or created for a single occasion or use.

Origin

• From Middle English nonse, nones, a rebracketing of Middle English to þan anes, for þan anes . The cryptography sense is commonly said to be a contraction of number used once, although this is probably incorrect.
• 1975.
• Unknown, derived from British criminal slang. Several origins have been proposed; possibly derived from dialectal nonce, nonse (but this cannot be shown to predate nonce "child-molester" and is likely a toned-down usage of the same insult), or Nance, nance, from nancy or nancyboy. The rhyme with ponce has also been noted.
• As prison slang also said to be an acronym for "Not On Normal Communal Exercise" (Stevens 2012), but this is likely a backronym.