alternate
back and fill
blow hot and cold
bob
bobble
careen
change
changeable
chop and change
coggle
dally
dallying
dangle
demurring
dickey
dillydallying
dither
double-minded
doubtful
doubting
ebb and flow
eccentric
equivocate
erratic
falter
faltering
fickle
fiddle-faddle
flounder
fluctuant
fluctuate
fluctuating
flutter
go through phases
halt
halting
hang in doubt
hem and haw
hesitant
hesitate
hesitating
inconstant
indecisive
insecure
irresolute
librate
lurch
mercurial
nutate
oscillate
swing
vacillated
vacillates
vacillating
vacillant
vacillation
vacillator
vacillatory