exercĭtor (noun M) : exerceo, II.
* An exerciser, trainer (ante- and post-class.)
* Prop.: huic Gurgulio'st exercitor, is hunc hominem cursuram docet,Plaut. Trin. 4, 3, 9; 2, 1, 4, Macr. Somn. Scip. 2, 14 med.
* Transf., one who exercises or practises any profession, business, calling: cauponae aut stabuli,an innkeeper,Dig. 44, 7, 4 fin.: navis, ratium,a ship-master, captain,ib. 14, 1, 1; 4, 9, 1; Inscr. Grut. 492, 5.

s. TLL