noli me tangere (L.), don't touch me.
nolle prosequi (L.), to be unwilling to prosecute.
nolo episcopari (L.), I do not wish to be a bishop.
nom de guerre (Fr.), an assumed name: travelling title: pseudonym [nom de plume is not French].
non compos mentis (L.), not of sound mind.
non est inventus (L.), he has not been found, he has disappeared.
non mi ricordo (It.), I don't remember.
non multa, sed multum (L.), not many things, but much.
non olet pecunia (L.), money does not stink—you can't tell how the money has been acquired.
non omnia possumus omnes (L.), we cannot all do everything.