The best way to learn proper English is to read news report, and watch news on TV. Watching TV shows is a great way to learn casual English, slang words, understand culture reference and humor. If you have already watched these shows then you may recall the words used in the following dialogs.

What's that little CLOT in the middle?
The Big Bang Theory Season 10, Episode 16

You still run the risk of infection,
a blood CLOT...
The Big Bang Theory Season 8, Episode 9