Discrete means "separate," while discreet means "unobtrusive." Both words have the same etymology coming from the Latin discretus which means "to keep separate" or "to discern." An easy trick to tell them apart is to remember is that the "e's" are separated by the "t" in "discrete."

What is the difference between discrete and discretion?

In the 1500s, discrete became more widespread, and so the spelling discreet came to prevail for its sense. One way to remember the difference between the two is that the noun form of discreet is discretion: You're showing discretion when you are being discreet. The noun form of discrete is discreteness.

How discreet is discreet?

Discreet means on the down low, under the radar, careful, but discrete means individual or detached. They come from the same ultimate source, the Latin discrētus, for separated or distinct, but discreet has taken its own advice and quietly gone its separate way.