Crash has different meanings in different ways using:
A ‘crash course’ is a short, intensive training course.
For example: He took a crash course in Australian before her holiday to Pari
To ‘crash and burn’ is to fail in a spectacular way.
For example: These people were only open for five months before the business crashed and burned.
To ‘gatecrash a party’ means to go to a party without an invitation.
For example: 25 people gatecrashed our party that we ran out of food.