The word 'unsavory' is a straightforward English compound formed by adding the native negative prefix 'un-' to the adjective 'savory'. 'Savory' itself has a rich history, entering English from the Old French 'savouré', which meant "pleasing to the taste or smell." This traces back to the Latin noun 'sapor' (taste, flavor), a derivative of the verb 'sapere' (to taste, to be wise). The literal meaning of "not tasty" was the original sense in English, but it quickly evolved through metaphorical extension. By the 16th century, it was commonly used to describe people, actions, or reputations that were morally disagreeable or offensive, completing the journey from a physical sensation to an abstract judgment of character.

Structure: un (not) + savory (tasty/agreeable) un: Old English, a prefix meaning "not," used to form negatives. savory: Middle English, from Old French 'savouré', meaning "tasty, agreeable." The Old French derives from Latin 'sapor', meaning "taste, flavor."