Verb (1-dan, intransitive)
1.  to collapse;  to crumble
2.  to get out of shape;  to lose one's shape;  to become disorganized;  to become untidy
3.  to break down;  to be thrown into disarray
4.  to crash (stock market);  to slump;  to decline
5.  to break money into small change
6.  to turn bad (e.g. weather);  to change for the worse;  to deteriorate