Lewis & Short

lănĭus, ĭi, m. [1. lanio], a butcher (cf. macellarius): lanii, qui concinnant liberis orbas ovīs, Plaut. Capt. 4, 2, 39; id. Ps. 1, 2, 63: cetarii, lanii, coqui, Ter. Eun. 2, 2, 26; Plaut. Trin. 2, 4, 6; cf. Cic. Off. 1, 42, 150: ab lanio cultro arrepto, Liv. 3, 48: cum de laniis aut vinariis ageretur, Suet. Claud. 40 init.; Varr. R. R. 2, 5, 11; Phaedr. 3, 4, 1.
Transf., an executioner (ante-class. and very rare): arcesse hostias, victimas, lanios, Plaut. Ps. 1, 3, 93 and 98.
Abusively, of a surgeon, Tert. de Anim. 10.