Unfriend is from un- ('reverse the action') + friend (verb, 'to add as a friend'). Though revived as social-media slang in the 2000s, unfriend as a verb is attested as early as the 17th century; friend derives from Old English frēond ('friend'). Important recorded forms include un- (Old English), frēond (Old English), and *frijōndz (Proto-Germanic). Morphologically, the un- element marks negation, reversal, removal, or deprivation, while the base supplies the action, quality, or state being denied or undone. The modern sense is largely compositional, with the historical elements narrowing into a stable English lexical item. In current use it covers to remove someone from one's list of contacts on a social network. The wider family includes derived forms such as unfriending and unfriended and related words such as friend, befriend, and friendly.