Lewis & Short

nūtātĭo, ōnis, f. [nuto] (post-Aug.).

  1. I. A nodding: capitis, Plin. 11, 37, 49, § 135.
  2. II. A swaying.
    1. A. Lit.: frequens et in utramque partem nutatio, Quint. 11, 3, 129.
    2. B. Trop., a shaking, tottering: nutatio reipublicae, Plin. Pan. 5, 6.