Green’s Dictionary of Slang

goofily adv.

foolishly.

1922		B. Hecht A Thousand and One Afternoons [ebook] They are kind of goofily romantic and they fall hard for everything and they spend their last penny on a lot of truck.
1933		E. Hemingway letter 3 Apr. in Baker Sel. Letters (1981) 384: G. Stein, who was a fine woman until she went professionally patriotically goofily complete lack of judgement and stoppage of all sense lesbian with the ole menopause.
1989		T. Blacker Fixx 14: Eventually Father extricated himself and [...] smiled goofily.