Groovy (or, less common, "Groovie" or "Groovey") is a slang colloquialism popular during the 1960s and 1970s. It is roughly synonymous with words such as "cool", "excellent", "fashionable", or "amazing", depending on context.

http://en.wikipedia.org/wiki/Groovy

That this needs to be explained makes me feel old.

I suspect that it is a geographical-cultural thing, not an age-culture thing.

edit: for clarity

Old people have different cultures.

It's both.

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.

It's as if Dude from "The Big Lebowski" had LinkedIn endorsements:

[ Groovy ][ Chilled ][ Fights "The Man"]

Wikipedia is OK, but I don't think anything can explain Groovy as well as Simon & Garfunkel:

http://www.youtube.com/watch?v=NvlW4bEjB5A

This might help - http://youtu.be/mWBvcJAXwu4 (Simon & Garfunkel)