Lewis & Short

1. mōlītĭo, ōnis, f. [molior], a putting in motion, moving, removing; a laborious undertaking, preparation, contrivance (rare but class.): molitio agrorum, a working, ploughing, digging, Col. prooem.: terrena, id. 11, 2, 98: facilis molitio eorum valli erat, a tearing out, demolishing, Liv. 33, 5, 6; a building, making, of the creation of the world, Cic. N. D. 1, 8, 19.
In gen., an enterprise, undertaking, Amm. 14, 9, 4.