The Brief: Oof is an exclamation of discomfort.

Bluesquiggle
DEEP DIVE

Oof is an interjection signaling discomfort. Users may incite the phrase when feeling overwhelmed, awkward, or generally at a loss. Oof can be used at the beginning or end of a sentence, or on its own. It is a ubiquitous term that can be used in reaction to almost anything.