ex tempore
extempore
spontaneously
impromptu
ad lib
ad libitum
unpremeditated
cold
extemporarily
extemporaneously
unprepared
off the cuff
off-the-cuff
offhand
unrehearsed
offhanded
extemporaneous
ad-lib
extemporary
out of the blue
nonfacilitated
unfacilitated
pending
unpracticed
ad-libbed
unexperimented
unconsidered
unprepped
unaccomplished
nonmanual
indextrous
unprocedurally
offhandedly
off the top of one's head
unsuccessfully
unaided
unenfolded
unplanished
unprocedural
nonprocessed
nonpreformed
unripe
unwinded
workmanlike
unfinalized
unsupplicated
on the hoof
methodless
unattempted
uninculcated