What is the meaning of Nonce?

The one or single occasion; the present reason or purpose.

A nonce word.

A value constructed so as to be unique to a particular message in a stream, in order to prevent replay attacks.

One-off; produced or created for a single occasion or use. Denoting something occurring once.

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.

nuncio

Source: wiktionary.org