What are five names for a horse that mean fast?for example flash or nitro

This sounds like a fun assignment. Are you actually naming
your own horse? I like your own suggestion of "Flash." You may want to check out some
synonyms of various words that relate to "fast" or "speed." A few that come to mind
are

• "Pronto"
  


• "Breakneck" 


• "Hell-Bent"
  


• "Instantaneous"


• "Stampede"


• "Headlong"


• "Charger"


• "Aftershock"


• any
  word combined with "thunder" ("Thunderbolt," Thunderstruck,"
  "Thunderclap").

You may want to consider giving
it a historical or mythological name that relates to speed or power, such as "Mercury"
(or "Mercurial") or "Apollo." I have also provided an interesting link that might be of
help. It gives hundreds of possible names--specifically for
horses.