“Double down” comes from blackjack, where you double your bet with a confident...
https://page-wiki.win/index.php/Why_Do_People_Misspell_%22Up_the_Ante%22%3F
“Double down” comes from blackjack, where you double your bet with a confident hand. In English, it means to commit fully, even if risk is high. Common learner slip? Saying “double up” instead—different meaning, don’t confuse the two. Keep your bets clear