impromptu
ad-libbed
extemporaneously
ad lib
offhanded
extemporarily
extempore
unpremeditatedly
cold
improvise
extemporise
improvize
extemporize
candid
ad-lib
extemporisation
improvisation
spontaneously
extemporization
ad libitum
cue-to-cue
extemporaneous
unimprovised
unpracticed
nonrehearsal
run-through
cold read
walk through
fall into
underchoreographed
wing it
designlessly
off the top of one's head
in at the deep end
unpremeditated
dry run
foretrained
ex tempore
unauditioned
off-the-cuff
offhand
offhandedly
unconsidered
scheduleless
improvisational theatre
on the hoof
all dressed up and nowhere to go
come stà
improvisatorial
nontipping