A more direct or literal translation of Geschicklichkeit would probably be something like or skilledness or skillfulness. Other words with the -lichkeit ending that might seem more familiar are Freundlichkeit (friendliness) and Brüderlichkeit (brotherliness)

The base word, Geschick, translates to ‘skill’ on its own. The difference is it strictly behaves as a countable verb, as in you can have a number of skills, just as you can have a number of friends, of brothers, etc. It doesn’t work when you want to describe a quality or property someone may possess, so that’s where the suffixes come in.

It’s the difference between “there’s a lot of friend here” and “there’s a lot of friendliness here”

In English, skill is an exception to a rule. It can be used in both ways, all on its own. You can use the suffixes anyways and, though it wouldn’t be the most efficient way of speaking, it wouldn’t even technically be incorrect since skill is flexible and can work in both ways. German, on the other hand, doesn’t generally make that kind of exception in the interest of maintaining consistency.

The Germans are probably going to roast me for this but that’s my understanding from just under 2 years of learning and a brief series of googles.