Expressing discomfort, as from sudden exertion or a blow to one’s body.
- I know a place on earth we can go, if you guys can - oof!
- Well you see he has some issues with some guy and we have some and - oof!
- She closed her eyes, trying to make it all go away and force herself awake, when she ran straight into a soft something that went oof!
natural exclamation: first recorded in English in the mid 19th century.
Entry from British & World English dictionary