E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
For the nonce. A corruption of for then anes (for then once), meaning for this once. An apron for a naperon is an example of n transferred the other way. We have some halfdozen similar examples in the language, as tother dayi.e. the other or thæt other = the other. Nuncle used in King Lear, which was originally mine-uncle. An arrant knave is a narrant knave. (See NAG.)