1. an unexpected or sudden upset, especially in a sports competition or election
Usage: informal; common in sports journalism
2. an instance of liquid boiling over the edge of a pot or container
Usage: literal, cooking context

1. to boil and overflow from a container
Usage: literal, cooking context

Examples

• The underdog team's victory was a major boilover in the tournament.
• The milk boiled over and made a mess on the stove.
• Nobody expected the boilover in the election results.
• If you don't watch the pot, the water will boil over.
• Sports fans love a good boilover when the top seed loses.
• The soup boiled over while I was answering the phone.