Top-shelf is a term that refers to something of the highest quality or superior level. Antonyms for top-shelf can be average, mediocre, or low-quality. If something is not top-shelf, it may be subpar, inferior, or low-end. Some other antonyms for top-shelf could include cheap, shoddy, or second-rate. Top-shelf items are often associated with luxury and excellence, so antonyms may also include words like basic, ordinary, or unsophisticated. In short, top-shelf is a term that implies excellence, and its antonyms allude to varying degrees of inferiority.