Definitions:

1. a natural event caused by something suddenly falling down or caving in noun
   • the roof is in danger of collapse
2. to break down, literally or metaphorically verb
   • The wall collapsed.
3. to fold or close up verb
   • I collapsed after a long day at work.
4. to lose significance, effectiveness, or value verb
   • The stock collapsed.

Synonyms:

• break
• break down
• break up
• crack
• crack up
• crash
• crock up
• flop
• prostration
• tumble