Break down

1. (Verb) Of a machine, to malfunction or break altogether.

2. (Verb) To fail or cease.

3. To destroy a physical structure. In this usage, a noun or pronoun can be used between "break" and "down."

4. To lose control of one's emotions, often sadness, especially after trying not to or after an intense buildup.

5. Break someone down: to force someone to give up and tell secrets or agree to do something. After threats of torture, they broke the spy down.

6. Break down (and cry):

to surrender to demands or emotions and cry. Max finally broke down and confessed.

7. Stop functioning, cease to be effective or operable.

8. To be divisible into smaller parts.

9. To fail despite effort; come to a stop: The negotiations between the warring nations broke down, and the fighting continued.