Hello everyone!
I have a bit of English slang for you today!

The slang is the word “flex” is a new slang way of saying “show off”

For example:
The new kid at our school was flexing so hard when he drove his fancy car to school every day.
Or
She is going to flex her new purse to all her friends.

Please keep in mind this is a very new slang used almost exclusively by younger English speakers - probably younger than the age of 30.

I hope you found this helpful! Thanks guys!