If a person is educable, they are able to learn — someone can teach them, and they can take the teaching in. It is an old, rather formal adjective. Teachers and doctors used it in reports, especially when they were talking about children who learned more slowly. Though actually, many people now find the word a bit cold, as if you are putting a label on someone rather than talking about them. In kind, ordinary English we more often say 'able to learn' or 'can be taught.' You may still meet educable in older books and in careful writing. There is a noun use too, in old school language, for a person judged able to learn, but that use feels dated.

可教育的（舊時較常用，現在口語多改說「學得會」）