An article in one of Sydney’s Sunday papers anonymously interviews drivers for senior members of our governments, including examples of the things they see or hear in the course of their job. It explains that ministerial drivers are
notoriously discrete
I would have expected them to stick together!
Discrete and discreet are often confused. I was surprised to find that they share an etymology in Latin discrētus, separate (and are also related to discern). Dictionary.com has a usage note (scroll down) which I won’t reproduce here.
Google Ngrams shows that discrete is most often used to describe time, event, Fourier (transform), values, set, points, units, particles, steps and components (all things), while discreet is used to describe man, person, silence, manner, men, persons, woman, use and management (all people or their behaviour).