A noun in The Etymologies of the 1930s glossed “doer, maker”, a combination of car- “do, make” and dîr “man”, used here as an agental suffix that cause i-affection on the preceding a, mutating it to e (Ety/DER). The d in this word is tricky to explain since after a vowel the suffix would be -nir (compare curunir), but Elaran suggested the initial element might actually be the gerund cared. See feredir for a similar example.

Neo-Sindarin: Some people have noted that there are no examples of suffix -dir causing i-affection in later Sindarin, and consider this Noldorin word dubious. Personally have no problem with ceredir, but I have ᴺS. caron “actor, agent, doer, maker” as an alternative. Fiona Jallings suggested ceredir may also have the sense “crafter [m.]”, with ᴺS. ceredis as its feminine equivalent (FJNS/340).