rock up
unplanned
all of a sudden
dead
suddenly
on the spur of the moment
short
of a sudden
abruptly
on impulse
intuitive
promptly
right away
autonomic
habit
open-ended
automatism
autoactive
reflexive
on the fly
catch
unstudiedly
involuntarily
out of the blue
throw
reflex
find oneself
unthoughted
spontaneously
instinctive
interrupt
creep up
snap
waylay
spawn
automaticism
come to hand
unexpectingly
expontaneous
ultroneously
extemporize
fire and forget
scramble
fall
motility
by accident
chop
extemporaneously
whap
turn up
reflexively
sally out
unanticipatedly
fumfer
chronoportation
sally forth
strike in
start
startle
unspontaneously
abrupt
jump
accidental
refractory
nonreactively
just like that
contrived
unscripted
show up
dodge
snatch
unforeseenly
by mistake
fortuitously
semispontaneously
nonjudgmentally
on the hop
autorepeat
all dressed up and nowhere to go
wade in
carelessly
aspontaneity
stunt
thrash about
strike
spring into action
unforcedly
overtake
go so far as
knee-jerk
autokinetic
jerk
put by
unsuddenly
inhibit