be all in

1. To be fully committed to a task or endeavor; to give or be prepared to give all of one's energy or resources toward something. Just so you know, I'm all in if you're serious about taking that cross-country trip next week. Don't start this renovation project unless you're all in—or willing to live without a shower for a while. I can't believe my junk-food-loving little sister is suddenly all in on yoga and wellness.

2. To be completely exhausted, fatigued, or worn out. I was all in after only the first mile of the race; I could barely even walk for the rest of it! Can we go back to our hotel room for a bit? After spending all day walking around the city, I'm all in. Let's just go home, the kids are clearly all in now.

all in, be

1. Be tired out, exhausted, as in I can't walk another step; I'm all in. [Slang; second half of 1800s]

2. In card games, especially poker, be out of money, as in I'm finished for the night; I'm all in. It refers to having put all of one's money in the pot. In his historical dictionary of slang, J.E. Lighter suggests that the gambling usage, first recorded in 1907, may be the source of the first sense.