Lewis Short
fluctŭātĭo (noun F) : id.
* A vibrating to and fro, a fluctuation (not ante-Aug., and very rare).
* Lit., a wavering motion, agitation: tunc artus trepidi, inquietae manus, totius corporis fluctuatio, Sen. de Ira, 2, 35, 3.
* Trop., wavering, hesitation, vacillation of the mind: in ea fluctuatione animorum opprimi incautos posse,Liv. 9, 25, 6; Vulg. Sirach, 40, 4.
Charlton T. Lewis, Charles Short, A Latin Dictionary