Green’s Dictionary of Slang

spooner n.

a flirt.

1910		Sun. Times (Perth) 20 Mar. 2nd sect. 9/1: hey Say [...] That a pair of Throssellville spooners got left behind at the Beach.
1922		M.E. Smith Adventures of a Boomer Op. 14: The parks are all open yet and full of Moonlight and Spooners.
1935		E. Pound letter Feb. in Paige (1971) 269: You can’t call them there bloody gallants, ‘cake-eaters’ or ‘lizards,’ ‘dudes,’ ‘gigolos,’ ‘young scum’ (I suppose my native tongue is still more flexible than English: ‘good for nothing young sprigs,’ ‘fils à papa,’ ‘spooners,’ ‘saps’).