Nutátio, onis, f. g. Verbale. Plin. Nodding, as one doth when he sitteth sleeping.
Lewis and Short: Latin dictionary
nūtātĭo, ōnis, f. [id.] (post-Aug.). I.A nodding: capitis, Plin. 11, 37, 49, 135. —II.A swaying. A.Lit.: frequens et in utramque partem nutatio, Quint. 11, 3, 129.—B.Trop., a shaking, tottering: nutatio reipublicae, Plin. Pan. 5, 6.