There's no such thing as an idle genius. An idle genius is an oxymoron.
I like to think of genius in terms of perspective and thus measure it by how rare and valuable a perspective is. Genius is the extreme form of insight. It's really not a measure of IQ, although a high IQ helps.
Getting to a rare perspective is usually a product of building up a mental framework and then seeing patterns in- and making associations or connections among seemingly unrelated phenomena. True genius is seeing associations among things previously unseen.
A high IQ gives you more ability to build the mental framework needed to see these associations, and a genius has actually applied it.
tl;dr an interview with five mensa members about how they perceive genius and their hi IQ peers. They mostly associate genius with accomplishment or creativity that expands a frontier.
Genius is a dynamic thing rendered via the lens of social value.
If scientific progress is our goal, then I would argue that forming cliques around a clique-governed definition of "most likely to elicit genius" is not only wrong, but dangerous. Heuristics can be ugly things.
Also, MENSA reminds me of church. Church is boring.
I like to think of genius in terms of perspective and thus measure it by how rare and valuable a perspective is. Genius is the extreme form of insight. It's really not a measure of IQ, although a high IQ helps.
Getting to a rare perspective is usually a product of building up a mental framework and then seeing patterns in- and making associations or connections among seemingly unrelated phenomena. True genius is seeing associations among things previously unseen.
A high IQ gives you more ability to build the mental framework needed to see these associations, and a genius has actually applied it.