1950's London, 2 well dressed Congolese doctors having a corridor debate in a hospital. Its 'phoom', says one. Its 'phoowm' says the other. Nasal English doctor sidles up, I think you'll find it's 'womb'. Nah, mate, they say. You wouldn't know about elephant flatulence.
Exclamation for a slam-dunk in basketball. Phoom!
Did you see that monster slam-dunk by LeBron James? He really phoomed it!
the explosion of something
When the lemonade in the glass is forazen it goes phoom.
When something goes "phoom" it is expanding. Instead of saying "expand" you would say "phoom".
The opposite is "soom".
Kassie - That marshmallow in the microwave is going phoom!!!.
Danielle - PHOOM.