the word "vinegary" is a straightforward english derivation from the noun "vinegar." the noun itself has a transparent history, originating from the old french vinaigre, meaning "sour wine," which is a compound of the latin words vinum (wine) and acer (sharp, sour). this literally describes the process of wine turning sour through acetic fermentation. by adding the native english adjectival suffix "-y," meaning "having the quality of," the word "vinegary" was formed to describe anything possessing the sharp, acidic taste or smell characteristic of vinegar. this meaning was later extended metaphorically to describe a person's sharp, sour, or irritable disposition, completing the journey from a literal description of a fermented liquid to an abstract characterization of temperament.

Structure: vinegar (sour liquid) + y (adjective-forming suffix) vinegar (from old french vinaigre, from latin vinum "wine" + acer "sharp, sour"); y (old english -ig, a common suffix forming adjectives meaning "characterized by, full of, having the qualities of").