(one's) bottom dollar
1. The last dollar one has available to spend. I put my bottom dollar on that bet. If I lose this one, that'll be the end of my Vegas run. Sorry, dude, I can't loan you anything—I spend my bottom dollar on that sandwich. Grandpa always tells us that he amassed his fortune by investing his bottom dollar.
2. A certainty that something will happen or be true. (Used almost exclusively in the phrase "bet (one's) bottom dollar.") I lost my umbrella, so you can bet your bottom dollar that it will rain tomorrow! Oh, I'd bet my bottom dollar that Kevin will be late tonight—he's never on time! Well, we know the rest of the family has already gotten to town, so if Mom's calling you repeatedly, I'd bet my bottom dollar they're making her miserable.
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.