Discreet and discrete are easily confused words. They are homophones, they sound identical, but are spelled differently and mean different things.
The spell-check application of most word processing software programs would not catch a slip-up of these two words. Spell-check is looking for words that aren’t in its dictionary, and words that resemble words in its dictionary but are possibly spelled wrong. Spell-check isn’t perfect. It doesn’t know and can’t guess what word you wanted or what word you meant, it can only judge the words on the page. If you used words that are all spelled correctly, it gives you a pass anyway.
Autocorrect suggests words that start with the same letters. It’s suggesting what word you may want to save time, but quite often, its suggestions are pretty off base. They don’t help you out, but they do make you laugh.
Discreet is an adjective. It means exercising caution and calm when speaking or behaving. Not gossipy, not throwing shade, or being loud.
Discrete is an adjective. It describes unique, distinctive parts that make up a whole.
The following story uses both words correctly:
Divyesh asked that the media and her own employees to be discreet about her newest client. A high profile children’s hospital was facing an embezzlement case involving all the members of its board. Reviewing the accounting for discrete departments within the hospital and contractors hired by the hospital was going to take time. No one needed to discuss the case or any findings.