The Collaborative International Dictionary of English v.0.48:
Fluctuate \Fluc"tu*ate\, v. i. [imp. & p. p. Fluctuated; p.
pr. & vb. n. Fluctuating.] [L. fluctuatus, p. p. of
fluctuare, to wave, fr. fluctus wave, fr. fluere, fluctum, to
flow. See Fluent, and cf. Flotilla.]
1. To move as a wave; to roll hither and thither; to wave; to
float backward and forward, as on waves; as, a fluctuating
field of air. --Blackmore.
2. To move now in one direction and now in another; to be
wavering or unsteady; to be irresolute or undetermined; to
Syn: To waver; vacillate; hesitate; scruple.
Usage: To Fluctuate, Vacillate, Waver. -- Fluctuate is
applied both to things and persons and denotes that
they move as they are acted upon. The stocks
fluctuate; a man fluctuates between conflicting
influences. Vacillate and waver are applied to persons
to represent them as acting themselves. A man
vacillates when he goes backward and forward in his
opinions and purposes, without any fixity of mind or
principles. A man wavers when he shrinks back or
hesitates at the approach of difficulty or danger. One
who is fluctuating in his feelings is usually
vacillating in resolve, and wavering in execution.