Refers to the act of graduating from school, college or a university; 'pass' as in 'get through' and 'out' as in, well, 'out of school/ college/ university'. Has nothing to do with the consequence of ten vodka shots on an empty stomach.
I'm passing out of Engineering this year man. And then I have to send my bio-data to companies to start interviewing. You see, I can propose Deepa only after I have a job in hand.
Mom: My son passed out of BMSCE with flying colours! I am thinking of doing a small pooja in Dodda Ganeshana Gudi and breaking a coconut. I hope no one puts eyes on my boy.
Neighbour: Yes, yes. He is a very decent and good-hearted boy who gives respect to elders. Convey him my blessings.