Board Thread:The Flash discussions/@comment-9346948-20161130010008/@comment-16581186-20161204155342

Never have I seen any source that says you need Speed Force connection to be considered a speedster, and I've seen the word "speedster" thrown around a lot in my many years indulging in DC media.

You just have to have to have Superspeed to be a speedster, or enough speed to break the laws of physics anyway.