The word 'veg' is a modern British English slang term, originating in the mid-20th century as a clipped form of 'vegetate'. The verb 'vegetate' itself comes from the Latin 'vegetare', meaning 'to enliven, animate'. The semantic shift is one of ironic reversal: from the Latin sense of active growth and life, 'vegetate' came to describe a passive, inactive, plant-like state of existence. The further clipping to 'veg' streamlined the term for casual speech, solidifying its association with idle relaxation, while the noun form 'veg' is a direct shortening of 'vegetables'.

This word is a clipping, a shortened form of the longer word "vegetable" or "vegetate." It is not composed of productive morphemes in its current form.