Superfast/ˈsuːpərfæst/ Definition 1 of 2Pro Tip 1/3Tech Context Used to describe advanced technology like internet and gadgets that operate quickly. I'm streaming in 4K because of my superfast broadband. Pro Tip 2/3Speed Importance Highlights an extraordinary achievement or superiority in speed. Our superfast shipping means customers receive orders the next day. Pro Tip 3/3Casual Tone Often used in casual conversation rather than formal writing or speeches. She finished her work superfast and went out with friends.