ad lib
extemporize
improvise
ad-lib
improvize
extemporise
cold read
extempore
cold
impromptu
ex tempore
unpracticed
extemporaneously
ad-libbed
solo
facile
warm-up
short
on the hoof
negate
spontaneously
ad libitum
preact
tölt
extemporization
extemporisation
improvisation
nonoperatively
extemporarily
predone
unprepared
botch
put by
go through the motions
aquacise
arrhythmic
rhythmless
parapraxia
like a duck takes to water
prepractice
make bricks without straw
taskless
jump before one is pushed
foreprepare
rhythmlessly
quick
immediate
uneffected
off the cuff
straightaway