fast
alert
apt
brief
compact
compendious
concise
curt
curtal
curtate
decisive
decurtate
expeditious
hair-trigger
immediate
instant
lightning-like
little
low
momentaneous
momentary
presto
prompt
punctual
quick
quick as lightning
quick as thought
rapid
ready
short
short and sweet
speedy
spontaneous
succinct
summary
swift
synoptic
transient
transitory
abrupt
continuous
inevitable
overwhelm
simultaneous
startle
sudden
Aeneas