Origin: 1625–35; alter. (with -u- of annual) of ML superannātus over a year old (said of cattle), equiv. to super ann(um) beyond a year + -ātus-ate1; see -ed2
"retired on account of old age," 1633, "obsolete, out of date," from M.L. superannuatus "more than a year old" (of cattle), from L. super "beyond, over" (see super-) + annus "year" (see annual).