discreet, adj.: 1. Careful and prudent in one’s speech or actions, especially in order to keep something confidential or to avoid embarrassment. 1.1 Intentionally unobtrusive (“a discreet cough”)
discrete, adj.: Individually separate and distinct.
(Definitions from Oxford Dictionaries.)
The words are related, but the two different spellings have been assigned to these distinct meanings in English. I mostly see people use “discrete” when they mean “discreet,” just because people are more likely to want “discreet” (especially in fanfiction), but I have seen the confusion going both ways.
Loki is the Philosopher King 