Am I misusing the word “smart”?
Yup. In general usage, “smart” means “good at one or some mental tasks”. (Your hypothetical example of Grigori Perelman is roughly analogous to the real example of Srinivasa Ramanujan.)
Yup. In general usage, “smart” means “good at one or some mental tasks”. (Your hypothetical example of Grigori Perelman is roughly analogous to the real example of Srinivasa Ramanujan.)