The term usability is used as a synonym of user-friendly, which is easy enough to translate into German: benutzerfreundlich (as an adjective) or Benutzerfreundlichkeit (if you need a noun). The concept is a very straight forward: user friendly are the things or processes that are easy to use, to learn, to memorize, things that are designed in a way that avoids mistakes and is efficient. It would seem that a usable thing is a thing just as it should be.
So it is strange that the concept is difficult to express in a short and snappy way in Spanish, but that is unfortunately the case. Of course one can explain the concept, that is easy because it is so evident, but it is also usually long and tedious. Not good for simultaneous interpretation. And saying something usable is just como Dios manda is too vague, I am afraid.
Perhaps usability is just another marketing fad that points the obvious. I remember when the Apple Corporation started marketing the then new iPod™. Somebody wrote at the time that Apple had chosen David and Victoria Beckham for their promotional campaign because if they could use the damn thing, then everybody could too. That was not nice to the Beckhams, but it must have hit the nail on the head, otherwise I would not remember it, would I?
But even if it is just a fad we must translate it when it is used in the original language.
Sometimes it is easier to express the opposite concept: when something is not user friendly it becomes farragoso, inmanejable, pesado. Would the opposite of the opposite then be infarragoso, manejable, liviano? I am afraid it does not sound good.
Can anybody tell me then what the proper word could be in Spanish?