speedy (adj.)

• abrupt
• agile
• alacritous
• alert
• apt
• breakneck
• brief
• brisk
• cometary
• cursory
• dashing
• decisive
• double-quick
• electrifying
• expeditious
• express
• fast
• feverish
• fleet
• flickering
• flying
• furious
• hasty
• headlong
• hurried
• immediate
• impetuous
• impulsive
• instant
• instantaneous
• last-minute
• light-footed
• lively
• mercurial
• meteoric
• nimble
• passing
• precipitant
• precipitate
• precipitous
• prompt
• punctual
• quick
• rapid
• ready
• reckless
• running
• sharp
• shocking
• short
• short-term
• slapdash
• smart
• snappy
• spanking
• spry
• startling
• sudden
• summary
• superficial
• surprising
• swift
• unanticipated
• unexpected
• unforeseen
• unlooked-for
• unpredicted
• urgent
• winged