I agree; I'm handwaving at the definition. FP as a 'thing' doesn't really exist, but we recognize languages that more and more embrace pure FP as an ideal, and

I agree; I'm handwaving at the definition. FP as a 'thing' doesn't really exist, but we recognize languages that more and more embrace pure FP as an ideal, and require greater and greater concessions away from imperative programming. There is likely a sweet spot in that continuum, but from someone solidly on the imperative side, the people falling somewhere on that continuum can appear arrogant, due to what imperative bits they have given up, even if it's not ~all~ the bits.