Friendship held an important place in the long eighteenth century. But one of the major challenges of everyday life was identifying friends from enemies. Few periodicals or treatises explicitly dealt with the subject of enmity, but it was always a central feature of the literature on friendship from this period, which contained abundant warnings about the perils of false friendship. The deepest enmities resulted from the closest friendships. Yet the candour and honesty of enemies had important social utilities. Probing the association between enmity and friendship opens up discussion about the tensions inherent in the sociability described, performed, and enacted during this period.