blowoff

noun

1. a current of escaping surplus steam, water, etc.: The safety valve released a violent blowoff from the furnace.
2. a device that permits and channels such a current.
3. Slang. a person who brags or boasts; a blow-hard.
4. a temporary, sudden surge, as in prices: The Federal Reserve Board’s credit tightening could cause a blowoff in interest rates.