Lewis Short
complēmentum (noun N) : compleo
* That which fills up or completes, a complement (rare; only fig.): numerorum (inania quaedam verba), * Cic. Or. 69, 230: omnium accusationum,that gives them their full weight,Tac. A. 3, 38: accusationis, Cod. Th. 9, 24, 3.
Charlton T. Lewis, Charles Short, A Latin Dictionary