From Wiktionary, the free dictionary
From the adjective efn, descended from Proto-Germanic *ebnaz.
efn-
- denoting equality: equal, equally
- efn- + eald (“old”) → efneald (“of the same age”)
- efn- + gōd (“good”) → efngōd (“just as good”)
- efn- + niht (“night”) → efnniht (“equinox”)
- efn- + heorte (“heart”) → efnheorte (“harmony, concord”)
- denoting togetherness: co-, fellow-
- efn- + cempa (“soldier”) → efncempa (“fellow soldier”)
- efn- + þrōwian (“to suffer”) → efnþrōwian (“to sympathize”)
- efn- + wyrċan (“to work”) → efnwyrċan (“to work together, cooperate”)
- efn- + wyrhta (“worker”) → efnwyrhta (“co-worker”)