'barf' originates from American English in the early 20th century, probably as an imitative or onomatopoeic word rather than from a specific older root.

'barf' appeared in early 20th-century slang and spread through colloquial speech and print; it did not come through a clear medieval or classical predecessor but developed directly as informal vocabulary.

Initially it meant 'to vomit' (an imitative term), and this core meaning has remained largely the same though its use broadened to figurative senses like 'to eject forcefully'.