1. To point out or expose the flaws in something. I hate to blow a hole in your argument against relocating, but the cost of living actually isn't that high there.

2. To take, use up, or deplete a large amount of money available in something, such as a budget, one's wallet, etc. The cost of repairing the car is really going to blow a hole in our savings. Tammy's private piano lessons are blowing a hole in my wallet!