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.

who will remain to DEFEND
the free people of Meereen?
Game of Thrones Season 6, Episode 3

You DEFEND these men
who insult you behind your back.
Game of Thrones Season 2, Episode 8

I have to DEFEND my girlfriend to you.
The Big Bang Theory Season 9, Episode 14

- You're going to have to DEFEND yourself.
- Why didn't you get up and fight?
Game of Thrones Season 1, Episode 4

which means the poor cunts trying to DEFEND
the city end up burning it down.
Game of Thrones Season 2, Episode 5