What is "unmemorable"

Usage examples of "unmemorable".

And, with eyes long accustomed to darkness, the guard would mark the other's face, burning it indelibly in the superb memory hidden behind expressionless, unmemorable features.

But unmemorable men could not have plotted such hideously memorable deeds.

He was just a nondescript person with unmemorable clothes and a face you might vaguely think you’d seen before.

His long, tanned face was unmemorable, though his eyes were sharp, possessed of intelligence.