spoony \SPOO-nee\ (adjective) - 1 : Foolish; silly; excessively sentimental. 2 : Foolishly or sentimentally in love.
"'I think every man is bound to do the best he can for himself -- that is, honestly; there is something spoony in one man allowing another to get before him, as long as he can manage to be first himself." -- Anthony Trollope, 'The Three Clerks'
Spoony is from the slang term spoon, meaning "a simpleton or a silly person."