Hi Lúthien,
As I said in John's explanation there is a notion of "pleasure" if someone is over-fond of something. In kefkayer, the element "kef" is from the arabic kif or kiff (also written keif), a word that has entered the French slang with the meaning "pleasure, be fond of" and which gives:
le kiffeur m. noun a person taking intense pleasure in something
la kiffeuse f. noun same as above
kiffer verb take pleasure
le kiff m. noun intense pleasure
and if you ask me what the exact translation of a "Párendil" is, my answer is:
Un kiffeur ou une kiffeuse qui kiffe le plus grand kiff "des mots".