Green’s Dictionary of Slang

(US) a person or thing that is loose, in any sense.

1958		E. Frankel Band of Brothers 5: ‘All mornin’ he’s been fidgety as a nigger in new shoes.’ ‘You wasn’t no loose goose when you first come here.’.
1969		D. Pendleton Executioner (1973) 113: Internal security is a loose goose, though.
1983		Goldman & Fuller Charlie Company 206: There remained in Bowen a wide streak of the roustabout—the rabble-rousin’ loose goose.