Would saying "Najla does such and such" be considered backbiting if Najla is unknown to the listener?

Scholars have stated that backbiting about an unknown person, when the listener is unaware of their identity, does not fall under the definition of backbiting. However, mentioning the name of a person who can be identified after investigation does constitute backbiting, even if the listener did not initially know them. Al-Nawawi said: "If the person is unknown and cannot be identified even after investigation, then some scholars consider there to be no harm in that," and "It is not backbiting unless one names the person by their name, or alludes to them in a way that makes them understood." A Muslim must guard their tongue and not mention people in ways they dislike, nor name them, for fear that they might become known, thus falling into forbidden backbiting.