Superadd, v. t. [imp. & p. p. Superadded; p. pr. & vb. n. Superadding.] — Webster enters it under “superadd”
Etymology: [L. superaddere. See Super-, and Add.]
To add over and above; to add to what has been added; to annex, as something extrinsic. The strength of any living creature, in those external motion, is something distinct from, and superadded unto, its natural gravity. Bp. Wilkins. The peacock laid it extremely to heart that he had not the nightingale's voice superadded to the beauty of his plumes. L'Estrange.
Shades of meaning
Fernald lists superadded only as an antonym, under inherent.
He lists it without comment; the entries above explain its neighbors.
Synonyms
none given