Well, in my defense, I know what it means to be groovy and sorry if post made it seem otherwise. What I was misunderstanding was the fact that you can actually endorse personality traits on people since I have made a point of staying as far away from LinkedIn as possible. I thought that you were only able to endorse skills, and so when I saw they were endorsed for a personality trait I was a little confused and wondered if they meant that as a skill trait :)
I interpreted the OP as saying that the uncle endorsed "Groovy" as a skill (presumably the programming language), but probably thought it was a personality trait.