Pui commonly has 3 usage.
1. Pui is a action forceful sound from spitting. Commonly used by hakka hokkien retired back alley workers usually after being quoted an unreasonable low amount for service.
2. Pui is a gas emitted from anus commonly known in hokkien as pang pui.
3. Pui is used to describe an overweight person. Ah pui or ah bui can be used.