スラング。おそらくフランス語のespirt「精神、活力」が語源で、語源的にはspiritと同じ。
The splore is a frolic, a merry meeting. In the slang language of the inhabitants of St Giles's, in London, it is called a spree or a go. [Note in "Select Scottish Songs, Ancient and Modern," vol. II, London, 1810]In Foote's comedy "The Maid of Bath" (1794) the word appears as a Scottish dialect pronunciation of spry: " 'When I intermarried with Sir Launcelot Coldstream, I was en siek a spree lass as yoursel; and the baronet bordering upon his grand climacteric;' " etc.