one
informal Used in place of an indefinite article to emphasize another modifier. You are one ugly son of a gun! Wow, that is one spicy burrito. It feels like my mouth is on fire!
the one
informal The person with whom one will share a lifelong romantic relationship; one's true love. I know you really like the woman, but how can you be so sure she's the one? You've only been on a few dates with her! Look, I'm not out here trying to find the one or anything. I just want to meet some cute guys and have a bit of fun.
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.