Lewis & Short

nătātus, ūs, m. [natator], a swimming (postAug.), Stat. S. 1, 5, 25: piscium natatu, Pall. 1, 17, 2: fluvios natatu scindere, Claud. IV. Cons. Hon. 347; cf. id. Rapt. Pros. 3, 333.