(idiomatic) Having suffered net losses; in debt.
(stud poker) Of a card ("the hole card") which is dealt face down and thus unknown to all but its holder; hence (idiomatic) in reserve; in particular ace in the hole.
Source: en.wiktionary.orgThis rule I propose, Always have an ace in the hole. Always try to arrive at Having an ace some place private. Cole Porter
I love to play golf, and that's my arena. And you can characterize it and describe it however you want, but I have a love and a passion for getting that ball in the hole and beating those guys. Tiger Woods
When I came to DreamWorks, I was in bad trouble. They were in bad trouble. They were millions of dollars in the hole and a few days from closing their doors. I was on my last leg. Toby Keith
I'm a right pain in the hole for my agent. I won't take certain parts if I think they're offensive or banal. For instance, I won't do a film if I think it's full of violence for violence's sake, or a television drama if I don't think it's intelligent writing. Anne-Marie Duff
At the British Open, I had my opportunities, but the ball just didn't want to go in the hole on the back nine. Fuzzy Zoeller
Don't go selling the hide while the bear remains in the hole. Yugoslav Proverb