Nescio Quis: A Little Latin for the Day

The Latin expression "nescio quis" has the potential meaning "somebody or other." It's often used in a contemptuous manner.

"Nescio quo pacto" denotes "in some way or other." Bennett's New Latin Grammar gives these examples:

Nescio quis forms a compound indefinite pronoun with the force of some one or other; as,—

    causidicus nescio quis, some pettifogger or other;

    mīsit nescio quem, he sent some one or other;

    nescio quō pactō, somehow or other.

See https://www.thelatinlibrary.com/bennett.html

Non nullus can be translated "not none," "some" or "several" (plural use).

Matthew 26:70 (Vulgate): at ille negavit coram omnibus dicens nescio quid dicis

Of course, in this passage, we have nescio, which is a 1st person verb.