You finally beat the hardest level. You turn to your friend, chin up, eyebrows raised, waiting for praise. That face is a ドヤがお.
What it means
ドヤ comes from どや, the Kansai way of saying どうだ, “how's that?”. Add がお (face) and you get ドヤがお: the proud face someone makes when they want you to notice what they did.
How to use it
You almost always hear it as ドヤがお, about someone else: ドヤがおです, ドヤがおで …. The person showing off doesn't say it; the people watching do.

みて ください! テストで ひゃくてんでした!
Look! I got 100 on the test!

すごいですね!
That's amazing!

でしょう?
I know, right?

…ドヤがおですね。
...You look so smug.
Close cousins
- えっへんa proud little cough, chest puffed out
- にやりa quick, knowing smirk
- どうだ“how's that?”, the standard Japanese behind ドヤ
In manga and anime
A smug character is drawn chin up, with a little smirk, and ドヤァ beside them. Fans share ドヤがお screenshots when a character shows off.
Can you use it?
Yes, with friends and online. Saying someone has a ドヤがお teases them, so keep it for people you are close to.