Apo 

Bengali word for sister. Except you don't use it unless you love your sister too much. Just like Jaime Lannister loves his sister Cersei Lannister in Game of Thrones. You could use this in a sentence like "Thanks apo apnio" which conveys the utmost form of gratitude towards the apo you are addressing.

Girl: Wow! You make killer memes!
Boy: Thanks apo apnio.
Girl: Don't come near me or my city ever again.

Apo by A_Random_Dude September 16, 2018

apo 

Alpha Phi Omega: National Co-ed service fraternity. Largest largest collegiate fraternity in the US. Founded on the 3 cardinal principals of Leadership, Friendship, and Service. Unlike many other fraternities, APO's primary focus is to provide volunteer service within four areas: service to the community, service to the campus, service to the fraternity, and service to the nation as participating citizens.

I joined APO when I found out it was the largest dating service in the US.

apo by Lou_ag November 22, 2009

APO 

Apo is a boy names in kurdistan and means uncle. Apo is a pen of Abdul Rahman Ojlān.

APO he's a good boy

APO by APO oslub August 18, 2018

APO 

Authorized Personnel Only

Hey , APO beyond that door!

APO by Mike February 15, 2004

APO 

Amusement Purposes Only - When you are married or have a girlfriend, but you have a little side piece of ass "For Amusement Purposes Only'

She aint girlfriend material - good for APO and that's about it.

APO by zajebisty1 March 6, 2004

APO 

Anti-Pants Organization

"Dude, where are your pants?"
"Man, I'm in APO. We don't wear pants."
"Um... I don't think that's what that means..."
"Dude, I was just at the APO house and none of those bitches had pants on."

APO by TurkeyBaster May 27, 2012

apo 

Asian Pride Only
When an asian will only talk to another asians.

White guy's friend "Check out that girl. You should ask her out."

White guy "No way man, its not worth it. She is APO."

apo by Steven May 13, 2005