Green’s Dictionary of Slang

two-foot rule n.

a fool.

1859		Hotten Dict. of Modern Sl. etc.
1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict.
1890–1904		Farmer & Henley Sl. and Its Analogues.
1927		Shields Dly News 2 Dec. 2/7: My ‘lean and fat’ (hat) blew off my ‘ball of lead’ (head) and I felt an awful ‘two-foot-rule’ (fool).