Contentious (philoneikos). Old adjective (philos, neikos), fond of strife. Only here in N.T. If he only existed in this instance, the disputatious brother.
Custom (sunētheian). Old word from sunēthēs (sun, ēthos), like Latin consuetudo, intercourse, intimacy. In N.T. only here and 1Co 8:7 which see. “In the sculptures of the catacombs the women have a close-fitting head-dress, while the men have the hair short” (Vincent).