all in adjective 4noun 2adverb 1forms 4 adjective4 •Having no further stake to wager, but remaining active in a hand.By betting his last $100, John was all in. •Totally committed.John is now all in on getting this product to market by year end, come hell or high water. •(old-fashioned) Very tired.[Yawn] Well, I'm all in! Time to turn in! Good night all! •(UK) With everything included. noun2 •A hand where at least one player bets all of his or her chips. •A player who is all in.Since she was against an all in, Jill had no reason to bet. adverb1 •Synonym of all in all. formsall ins · all-ins · more all in · most all in