RapidFi ...
Fi...
Fidelity (as in HiFi) ... XFi... Any description of speed doesn't work with it
If it was Fl (ef-el) it might have some greater potential.
As an acronym...
Field Intensity
Food Intake
Foreign Intelligence
Final Inspection
Fault Isolation
Financial Investor
Fuel Injection
Financial Inspection
Family Income
Its a relatively short domain name and has some potential in various industries when considering acronyms, however, a domainer isn't interested in long-shot concepts and selling to a business is going to be hard work and uneconomical.
I think there is selling potential if its low priced and if you are able to indicate value on a site like flippa or ebay... beginners might bite, as they generally make the mistake of believing in a concept or potential rather than thinking about how much you can make reselling it. Of course, many buy to develop without getting time to do so.
Might be $200 or so if you are lucky. probably take a while of relisting etc.
Just noticed you have it as an auction on flippa! good luck.