"a frolic, drinking bout," 1804, slang, earliest use in Scottish dialect works, of uncertain origin. Perhaps [Barnhart] an alteration of French esprit "lively wit" (see esprit). According to Klein, Irish spre seems to be a loan-word from Old Norse sprakr. Watkins proposes a possible origin as an alteration of Scots spreath "cattle raid," from Gaelic sprédh, spré, "cattle; wealth," from Middle Irish preit, preid, "booty," ultimately from Latin praeda "plunder, booty" (see prey (n.)).
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.