fast
abrupt
agile
alacritous
bluff
bold
breakneck
brisk
ceaseless
chattering
chute
constant
continual
dalles
dashing
double-quick
eagle-winged
expeditious
express
fleet
flying
galloping
hair-trigger
hasty
headlong
high-speed
hurried
hustling
immediate
impetuous
incessant
instant
instantaneous
light of heel
light-footed
lively
machine gun
mercurial
nimble
nimble-footed
oscillating
perennial
perpetual
plunging
precipitate
precipitous
prompt
pulsating
quick
white-water
waterway
rapt
gradual
subsequent
vigorous
vapid