Discreet vs. Discrete

If you are careful in your judgment and don’t draw attention to what you’re doing, you are discreet (noun form: discretion):

showed discretion in his decision not to tell others about the matter
FBI agents discreetly kept tabs on the suspect

Things that are separate or distinct from one another are discrete (noun form: discreteness):

discrete entities that should not be treated as if they were the same

One way to remember the difference in both spelling and meaning between these two words is to note that the e’s in discrete are separated by the t.