Look at it this way. Your abilities/worth/knowledge/whatever are multidimensional and can be mapped on a "Radar Chart"(https://en.wikipedia.org/wiki/Radar_chart). They can also be classified as "Inherent" or "Incidental/Accidental". Thus there can be no single "smartness" index defining a person.

Thus for example, i am "un-smart" on both Web Dev and Statistics/Probability axes. The former is Incidental and easily fixed in a couple of months of work but the later is Inherent and needs a lot more time for assimilation. Thus the same word "un-smart" actually conveys two different meanings in the two different axes and one should not conflate the two.