I remember reading a biography of George Orwell in which Orwell and A.J. Ayer met in a hotel in France and spent an evening together (in the hotel bar, I hasten to add). The biographer (with a literary background) described them whimsically as 'two men of near-genius'.
Is the concept of genius pointless? If it depends who you ask, surely it is - John Lennon, Babe Ruth, Jackson Pollock, etc. and it can't simply be a question of aesthetics when applied to Newton or Aristotle, say. I reckon there are no criteria outside of a dictionary. How does philosophy deal with such vague terms?
I wanted to respond to the suggestion in your question that if a term is vague it is thereby "pointless" -- that doesn't seem right to me. For example, although the term "bald" is vague -- we can't specify the precise number of hairs a person must have (or not have) to count as bald -- the term is by no means pointless. Perhaps there are some borderline cases where we don't know whether to call someone bald or not (Jason Alexander? Bald? Or just balding?). But that doesn't mean that there aren't plenty of clear cases: Howie Mandel, bald; Suri Cruise, not. [Aside: see here if you're concerned about bald babies.] And so the term "bald" is perfectly useful in everyday speech. [Another aside: interestingly, Wikipedia lists Jason Alexander among their famous bald people , but I'd call him a borderline case. The entire list seems suspect to me, anyhow -- why is Matthew McConaughey on the list? But philosophers are well-represented: Foucault, Whitehead, and Wollheim all make the list.] ...