From the Japanese kekkon, meaning marriage and the English owned, meaning defeat.
To ruin one's life by deciding to get married too young and/or to someone who ensures one's lifelong misery.
"Hey, did you hear that Ken proposed to Barbie?"
"Are you kidding? They're only 19!"
"I know... Plus, she's a controlling bitch, she takes all his money, and all his friends hate her."
"Wow, that poor bastard's gonna get kekkOWNED!"