In practical terms: A Korean word that refers to the act of people (particularly Korean girls) employing a sickeningly cutesy behavior in an attempt to appear attractive (usually towards boys).
When using aegyo, girls tend to speak in incredibly annoying baby-talk voices. This girl sitting next to me at a coffee shop is using this voice on her boyfriend right now and it's taking all my self-constraint to stop myself from reaching across the table and strangling her. But ya know, her boyfriend just bought her coffee and about ten pounds of sweets so I guess it's working pretty well for her.....
Aegyo tip: If you want to be excellent at contemporary aegyo, when speaking to a boy, *always* call him oppa
. Yes, even if he's younger than you; who cares about the word's *actual* *correct* usage! Just go ahead and call him oppa anyway, you annoying little fuck, you. And remember: if you say "oppa" after practically every other word, the effect is even more powerful! Wow! (sarcasm)
Aegyo girl: Oppa~! My little belly is so rumbly~ will you take me to a fancy restaurant and pay for everything?? Please, oppa? Oppaaa~~
boy: OF COURSE ANYTHING I'LL DO ANYTHING (but actually I just want to take you to a love motel and get into your Hello Kitty-print panties)
Aegyo girl: Yay~!! Oppa...thank you~^^! But oppa, don't forget to take me to noraebang
later and pay for that too, oppa~! SARANG HAE OPPA~!!11!!~!one!!! OOOPPPPPAAAaaAAa
Everyone else in the room: *suicide*