break down

fe’l verb

1. To fail, to cease to function. I am afraid my computer will break down if I try to run it at too high a speed.
2. To render or to become unstable due to stress, to collapse physically or mentally. She is back to work now, after she broke down the other day.
3. To render or to become weak and ineffective. His authority and influence over his coordinates broke down gradually.
4. To (cause to) decay, to decompose. Leaves and grass will break down into compost faster if you keep them moist.