You know how the dwarves have curses like ‘Ish Kakhfê ai’d dur rugnu’? (which most likely translates to 'fuck you and your eyebrows’) Well, since the elves are far more 'wise’ (everyone who has read the Silm knows that is a lie ) the elves would probably curse Fëanor’s name.
Like, got surrounded by orcs? Blame it on Fëanor, he made the Noldor leave Valinor. Got rejected by your crush? Blame it on Fëanor, he was estranged from his wife because she wouldn’t go with him. Got family problems? Blame it on Fëanor, his family drama literally shattered a continent. Got too much homework? Blame it on Fëanor, he created the Tengwar script. Got dumped? Blame it on Fëanor, he literally dumped his brother and nephews in a frozen hell. Sauron’s got his eye on you? Blame it on Fëanor, he made the palantiri. Giant spiders? Sick forests? Fëanor wouldn’t give up the silmarils even when he didn’t have them, blame it on him.
This list could keep on and on, because let’s face it: no matter how much we love him we have to admit that he is a little shit. He is the cause of the doom of the Noldor and its woes. The elves would probably curse something like, 'Fie upon thee, Fëanáro, for thy deeds have damned us all!“ or "Thrice I curseth thy name, Fëanor, for this woe is the work of thee!” or just a good old 'GET THEE GONE FËANOR!“
I think even his sons eventually cursed his name as well, so then this gets passed down to Elrond. So when something bad happens to him (which happens often) he is like "curse thee, great, great granduncle!”
I think Galadriel was the one that started the tradition, along with Fingolfin and basically everyone that crossed the Helcaraxe. I think that the last words Fingolfin uttered while Morgoth stepped on his throat were 'FUCK THEE, CURUFINWË FËANÁRO!“
On the other side, Fëanaro always called the Nolofinwëans the 'nolofuckers’ so I guess that is their way of expressing brotherly love.