spoony \SPOO-nee\ (adjective) - 1 : Foolish; silly; excessively sentimental. 2 : Foolishly or sentimentally in love.
"There is no doubt whatever that I was a lackadaisical young spoony; but there was a purity of heart in all this, that prevents my having quite a contemptuous recollection of it, let me laugh as I may." -- Charles Dickens, 'David Copperfield'
Spoony is from the slang term spoon, meaning "a simpleton or a silly person."