Entry 1 sense Webster, 1913 Supervacaneous /so͞o'pərvəkāʹnĭəs/ · Su·per·va·ca·ne·ous · IPA /ˌsuːpəɹvəˈkeɪnɪəs/ 01 a. Serving no purpose; superfluous; needless. 1. Serving no purpose; superfluous; needless.[Obs.]