It seemed to them the ideal place for those confidential mid-morning potations and games of pool for which the Foreign Office had invented the phrase “elevenses”, after the hour of the morning when one feels one most needs a short swift drink, or a long “unwinder”, to use slang.
Source: wiktionary
2010, William Campbell, Apotheosis, Glyd-Evans Press, p. 137,
In contrast to the overwhelming sweetness, the cool drink is bitter like coffee, but with a strong bite of alcohol. One sip and I hand it back. Not the time for that sort of unwinder.