glee: [OE] Glee has had a strange history. It was common in Old English times, both for ‘entertainment, having fun’ (source of the modern sense ‘joy, delight’), and in the more specific sense ‘musical entertainment’ (from which we get the ‘unaccompanied part-song’ of glee clubs). It survived healthily into the 15th century but then went into long-term decline. By the 17th century it seems virtually to have become extinct.
However, in 1755 Dr Johnson in his Dictionary said that it was ‘not now used except in ludicrous writing, or with some mixture of irony and contempt’, signalling the start of a revival which got fully under way towards the end of the 18th century. How and why it came back from the dead in this way is not known. Its source was Germanic *gliujam. [glee etymology, glee origin, 英语词源]